Glossary: Find Terms and Acronyms - Yenra

Memory designs that use a third dimension to arrange storage structures. The linked guide distinguishes layered semiconductor memory from other uses of “3D memory”; the label alone does not specify a device architecture.

Related coverage: 3D Memory Explained: NAND Layers, HBM, and Stacked Cache

A generation of cellular systems that supported mobile voice and data, including UMTS and related technologies. Availability depends on the network and country; use the mobile-network guides when identifying older equipment.

Related coverage: 3G explained: technology, networks and legacy

The fifth generation of mobile-network technology, including 5G radio access and associated system capabilities. Available service depends on the handset, spectrum, radio conditions, network deployment and supported features. Read a 5G indicator as a connection label; assess actual coverage, throughput and delay for the task you need to perform.

Guide: 10 Technologies That Benefit from 5G and What They Require

Reference: 3GPP: 5G system overview

Compare: LTE, Wi-Fi, Throughput, Latency

Advanced Audio Distribution Profile: a Bluetooth Classic profile for distributing media audio from a source, such as a phone, to a receiver, such as headphones. Both endpoints need compatible profile and codec support. Hands-free call audio uses a different profile, and playback-control commands are a separate part of the device’s supported functions.

Guide: Bluetooth Audio: Compatibility, Sound Quality, and Troubleshooting

Reference: Bluetooth SIG: Advanced Audio Distribution Profile

Compare: Bluetooth profile, HFP, Codec

An antenna's gain in a specified direction relative to an ideal isotropic radiator, using consistent power and polarization conditions. The reference matters when comparing antenna specifications.

Reference: NTIA: antenna gain and patterns (PDF)

The name a browser determines for an interface element and exposes to assistive technology, helping users identify its purpose. It may come from visible label text, element content or an explicit naming attribute. Check the computed name in context, keep visible wording consistent, and use a separate description for additional instructions when needed.

Guide: Accessibility Evaluation and Repair: From Finding to Retest

Reference: W3C: accessible names and descriptions

Compare: Form label, Screen reader, Semantic HTML

An optical system that measures changing distortions in incoming light and rapidly adjusts a deformable mirror to reduce them. Ground-based telescopes commonly use a reference star or laser-created beacon to sense atmospheric effects near a target. Correction quality depends on observing conditions and the system, so compare corrected images at stated wavelengths and angular scales.

Guide: Laser Guide Stars: How Adaptive Optics Sharpens Telescope Images

Reference: ESO: adaptive optics and guide-star references

Compare: Angular resolution, Diffraction

Advanced Gateway Server, an early Cisco router product. Historical specifications describe the particular hardware generation and should be kept separate from present-day networking requirements.

The time radio transmissions occupy a wireless channel. Data, management traffic and retransmissions all consume this shared resource; sending the same payload at a lower radio rate generally takes longer. When a busy network slows down, examine channel use and retries alongside signal strength and internet capacity to locate the constraint.

Guide: Wi-Fi Channel Planning: Balance Width, Reuse and Airtime

Reference: Cisco Meraki: capacity planning and management-frame airtime

Compare: Channel width, Throughput, RSSI

Ambiguity created when different signal frequencies produce indistinguishable sampled values. With inadequate sampling for the input bandwidth, a changing signal can appear at a false lower frequency. Choosing a suitable sample rate and filtering unwanted higher-frequency input before sampling helps prevent this. Sampling more often also needs a sensor that can follow the underlying change.

Guide: Data Loggers: Plan a Measurement You Can Trust

Reference: NI: sampling, bandwidth and aliasing

Compare: Sample rate, Sensor response time, Interpolation

The Atacama Large Millimeter/submillimeter Array, a radio observatory whose antennas work together to study the universe at millimeter and submillimeter wavelengths. An array's baselines help determine the angular detail it can resolve.

Related coverage: Radio Telescope Antennas: How Arrays Make an Image

A text alternative that conveys an image’s information or purpose in its context. A screen reader can present it to someone who cannot see the image. Informative images need useful equivalent meaning, while purely decorative web images generally use an empty alternative so they do not interrupt reading.

Guide: Astra QuickTest and Accessibility Regression Testing: From Recorded Actions to Useful Checks

Reference: W3C: image text alternatives

Compare: Screen reader, HTML, OCR

Active-matrix organic light-emitting diode: a display arrangement that uses an active matrix to control light-emitting pixels. The display technology name is one part of a screen specification, alongside resolution, brightness and other properties.

Related coverage: HP iPAQ Glisten

Advanced Medium-Range Air-to-Air Missile, the name of the AIM-120 missile family. A useful program description identifies the variant, platform and source date because the family has developed over time.

Related coverage: AMRAAM Explained: AIM-120 Variants, Platforms, and Program History

The smallest angular separation at which an observing system can distinguish nearby features or sources. Astronomers commonly express it in arcseconds; smaller values indicate finer detail. Wavelength and aperture set an ideal diffraction scale, while the atmosphere, optical quality and detector sampling affect delivered images. Magnification enlarges the view without automatically improving this resolving ability.

Guide: Infrared Telescopes: Wavelengths, Thermal Background and What Images Reveal

Reference: NASA: angular resolution, aperture and wavelength (PDF)

Compare: Diffraction, Adaptive optics, Spatial resolution (imagery)

Security software that detects, blocks or removes known or suspicious malicious activity using methods such as signatures and behavioral analysis. Its findings need interpretation, and protection also depends on updates, backups and other controls.

Read the guide: Antivirus Protection: What You Need and How to Check It

Reference: Microsoft: virus and threat protection

Adaptive predictive coding: a signal-coding approach that adjusts its prediction to the signal being encoded. A codec specification is needed to establish the particular algorithm and data format.

American Power Conversion, the company name behind the APC power-protection brand. Compatibility and capability depend on the particular product model; the linked guide explains battery and power-bank checks.

Related coverage: Laptop Batteries and Power Banks: Compatibility, Health, and Runtime

The lens opening through which light passes, commonly described by an f-number. At a given focal length, a lower f-number means a larger opening and more light during the same exposure time. Aperture also affects depth of field; many phones have a fixed physical aperture, even when software simulates background blur.

Guide: Landscape Photography: Plan the Frame, Light, and Exposure

Reference: Nikon: aperture and depth of field

Compare: Depth of field, Shutter speed, ISO (photography)

Access that an operating system grants an application to a protected capability or data, such as the camera, microphone, contacts or location. Available controls depend on the platform and can limit when access is allowed. Match each permission to the task, and review the app’s handling of collected data separately from the device’s permission setting.

Guide: Mobile App Security and Privacy: Review Access Before Adoption

Reference: Google: managing Android application permissions

Compare: Authorization, Least privilege, Mobile device management

Application-specific integrated circuit: a chip designed for a particular set of functions. Networking devices may use ASICs for packet processing and other tasks with defined performance requirements.

Automatic Switching of Network Access Points, a name used in historical dual-network mobile-phone coverage. Read it in that system's context rather than as a universal name for Wi-Fi or cellular handover.

Related coverage: Wi-Fi and Cellular Switching: Calls, Data, and Handoff Tests

The ratio of an image's width to its height, such as 3:2 or 4:3. Printing or displaying it in a different-shaped frame requires cropping, added borders or distortion; pixel dimensions are a separate specification.

Read the guide: CMOS Image Sensors: Size, Pixels, Noise and Shutter Readout

Asynchronous Transfer Mode: a connection-oriented networking technology using fixed 53-byte cells. Virtual connections organize traffic through the network; the acronym here refers to telecommunications rather than a cash machine.

A judgment assigning an artwork to an artist, workshop, school or period. The wording expresses the strength and scope of the claim; assess the supporting research and evidence alongside the label.

Read the guide: How the Art Business Works: People, Records and Provenance

Reference: Getty: creation and attribution

ARC sends audio from a television back to a compatible soundbar or AV receiver over HDMI, including audio from TV apps. Enhanced ARC, or eARC, provides a higher-capacity return path supporting additional audio formats. Check both devices’ supported ports, formats and settings; CEC handles control commands rather than carrying this audio.

Guide: HDMI: Choose the Right Connection and Troubleshoot It

Reference: HDMI: ARC and enhanced ARC

Compare: HDMI, CEC, PCM (audio)

The selection of paths that carry sound from sources to outputs, and microphone input to an application or call. A phone can direct music to a car stereo while a call uses another connected device. When sound is missing or misplaced, check the active input and output at each stage as well as its volume.

Guide: Bluetooth Car Stereo: Setup, Missing Audio, and Upgrade Options

Reference: Google: Bluetooth media and call-audio destinations

Compare: HFP, A2DP, Bluetooth multipoint

Audio data delivered progressively so playback can begin before a complete program has been downloaded. The stream's codec, address, access requirements and delivery reliability affect whether a player can use it.

Read the guide: Internet Radios: Choose a Receiver, Find Stations, and Set It Up

Checking evidence that an entity is who or what it claims to be. A password, security key or certificate may participate in that check; authorization separately determines what the authenticated entity may do.

Read the guide: Web Service Security: Access, XML Parsing, and Resource Limits

Reference: OWASP: web-service security

Compare: Authorization

Deciding whether an entity is permitted to perform an action or access a resource. Enforcing permissions for each relevant request helps keep a valid login from gaining unintended access.

Read the guide: Web Service Security: Access, XML Parsing, and Resource Limits

Reference: OWASP: web-service security

Compare: Authentication

The proportion of a defined period during which a service meets its agreed usable state. A percentage is meaningful only with a measurement period, service boundary and treatment of excluded downtime.

Association of Volleyball Professionals, the professional beach-volleyball organization referred to by this acronym. The sports context distinguishes this use from unrelated business and technical abbreviations.

Related coverage: Beach Volleyball: Rules, Scoring and What to Watch

An audio/video receiver that selects and routes sources, processes audio and usually includes power amplifiers for several speaker channels. It can act as the connection hub for a home theater. Supported formats, inputs, speaker assignments and amplification vary by model, so plan around the actual manual and connected equipment.

Guide: AV Receiver Setup: Inputs, Speakers, and Listening Modes

Reference: Yamaha: the AV receiver as a system hub

Compare: HDMI, Crossover (audio), Speaker impedance

The central network links and systems that carry traffic between other parts of a network. What counts as the backbone depends on the network's topology and organizational boundaries.

An undocumented or concealed access mechanism that bypasses a system’s expected controls. Malware may install a backdoor that accepts remote commands, giving an intruder a way to return. Investigating a compromise therefore includes checking for continuing access as well as removing the initially detected malicious file.

Guide: Mydoom: Deceptive Email, Backdoors, and the Scope of Recovery

Reference: NIST: backdoor

Compare: Malware, Authorization, Computer worm

A link that carries traffic from an access site or local network toward an upstream network. In a mesh deployment, access points may use wireless backhaul between nodes before reaching a wired gateway. Identify which paths share capacity and power: good coverage near a client can coexist with a constrained upstream connection.

Guide: Outdoor Mesh Networks: Backhaul, Capacity, and Recovery Tests

Reference: Cisco Meraki: mesh backhaul paths and deployment

Compare: Backbone network, WAN, Throughput

A retained copy of files, settings or a system, made so they can be recovered after loss or damage. A useful backup has a recovery path that survives the failure you are planning for. Check that representative files can be restored; synchronization can also copy unwanted deletions or changes.

Guide: Toshiba XG5-P Client NVMe SSD: Compatibility and Upgrade Checks

Reference: NIST: backup

Compare: Restore (data), Checksum, SSD

The data-carrying capacity of a network link or service, commonly expressed in bits per second. Delivered throughput also depends on overhead, contention and the endpoints. In radio engineering, bandwidth can instead mean a range of frequencies.

Read the guide: Technology Terms That Help You Read Product Specifications

Compare: Throughput, Latency

Radio equipment and antennas that connect wireless user devices to a network. Its capabilities depend on the radio system, frequency bands and network configuration.

Related coverage: Omni Cell Base Stations: Coverage, Capacity, and Rural Networks

The number of signaling symbols transmitted per second, measured in baud. In a conventional binary asynchronous serial link, one symbol carries one bit, but start, stop and optional parity bits also occupy the link. Match the devices’ serial settings and account for this framing when estimating useful payload throughput.

Guide: Replacing a Serial Cable with Bluetooth: Reliability and Recovery Tests

Reference: Keysight: serial baud rate expressed in symbols per second

Compare: Bit rate, RS-232, Flow control

Bubbling fluidized bed: a combustion arrangement in which upward-flowing air suspends a bed of particles. In biomass-boiler discussions, it describes part of the combustion process; fuel and emissions requirements still depend on the installation.

Related coverage: Biomass Boilers: Evaluate Fuel, Heat Demand and Operating Requirements

Broadband Global Area Network, a satellite communications service family used with compatible terminals. Service coverage, subscription and terminal capabilities determine what a particular connection can provide.

Related coverage: BGAN: Plan a Portable Satellite Connection for Field Work

A binary digit with one of two values, conventionally 0 or 1. Lowercase b denotes bits in common data-rate symbols; eight bits make one byte.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: NIST: bits, bytes and prefixes

Compare: RAM, SSD, Byte

The number of bits represented or transferred per second. For encoded media, it describes the data rate of a stream and may be fixed or variable. Network transport can add headers and other overhead, so a codec’s stated bit rate and the total connection demand can differ.

Guide: Speech codecs: why phone-call quality changes

Reference: RFC 4867: speech-codec rates and transport

Compare: Bit, Mbps, Bandwidth (network capacity), Throughput

Grouping comparable experimental units or runs according to a known nuisance factor, such as day, batch or operator, so treatment comparisons can account for that source of variation. In a randomized block design, treatments are assigned within blocks using randomization. Blocking and randomization therefore perform complementary jobs in the design.

Guide: Research Design Tools: Turn a Question into a Testable Experiment

Reference: NIST: randomized block designs

Compare: Experimental unit, Randomization (experiments), Confounding

A way of presenting storage as individually addressable blocks rather than named files and folders. A host can place a file system or an application's data structures on the resulting volume. A storage area network can supply block devices over a network; block storage describes the access model, not a particular disk type or a backup method.

Guide: Disk Storage Systems: Match Architecture to Workload

Reference: IBM: block storage and SAN volumes

Compare: File system, NAS, DAS

A family of wireless technologies operating in the 2.4 GHz band for communication between devices. Bluetooth Classic and Bluetooth Low Energy have different radio characteristics; matching a profile or service matters as well as the version.

Related coverage: Bluetooth Guides: Audio, Devices, Cars, and Development

Reference: Bluetooth technology overview

Keeping the security keys created during Bluetooth pairing so devices can use them in later connections. This remembered relationship can support reconnection without repeating the initial setup. An active connection and permission for a particular service are separate states; use the device’s documented forget or remove procedure when retiring a relationship.

Guide: Bluetooth Security: Pairing, Permissions, and Practical Protection

Reference: Bluetooth SIG: stored keys and subsequent connections

Compare: Bluetooth pairing, Bluetooth, Authorization

A Bluetooth radio technology designed for low-power communication in the 2.4 GHz band, also called Bluetooth LE or BLE. It supports uses such as sensor data, device control and supported audio systems. Actual energy use and interoperability depend on the hardware, software, traffic and implemented services; the LE label alone does not specify every available feature.

Guide: Choosing a Bluetooth Module for an Embedded Project

Reference: Bluetooth SIG: Bluetooth Classic and LE technology

Compare: Bluetooth, GATT, Bluetooth profile

The ability of a supported Bluetooth accessory to maintain connections with more than one source device, commonly a phone and computer. A headset can use this to switch music sources or handle an incoming call. Supported combinations and switching priorities vary; maintaining two connections does not imply mixing both audio streams.

Guide: Bluetooth Audio: Compatibility, Sound Quality, and Troubleshooting

Reference: Sony: simultaneous device connections and playback switching

Compare: Bluetooth profile, Bluetooth pairing, Bluetooth bonding

The Bluetooth security procedure that creates shared secret keys for communication between devices. The available association method and the devices’ capabilities affect how that relationship is established. Confirm the intended devices during setup. Bonding stores the resulting keys for later connections; permission to access contacts or other services is a separate decision.

Guide: Bluetooth Security: Pairing, Permissions, and Practical Protection

Reference: Bluetooth SIG: pairing, bonding and security architecture

Compare: Bluetooth bonding, Bluetooth, Authorization

A specification of Bluetooth capabilities and behavior for a particular interoperable use. Profiles define requirements beyond the core radio connection, such as the functions needed for conventional media playback or hands-free calls. Check the profiles, roles and optional features supported at both ends when evaluating compatibility.

Guide: Bluetooth Audio: Compatibility, Sound Quality, and Troubleshooting

Reference: Bluetooth SIG: profiles and service interoperability

Compare: Bluetooth, Codec, Bluetooth multipoint

An optical-disc format using a blue-violet laser and supporting higher data capacity than DVD. Standard Blu-ray and Ultra HD Blu-ray have different playback requirements, so check the exact disc and player format.

Read the guide: How to Play DVDs Today: TVs, Computers, Consoles, and Portable Players

A paper or accepted digital document issued through check-in for boarding a particular flight. It identifies the passenger and flight and is presented at the relevant airport checkpoints. A booking reference retrieves a reservation; the boarding pass serves the boarding process. Follow the airline's accepted format and obtain an updated pass when required after itinerary changes.

Guide: Airline Check-In: Booking References, Boarding Passes, and Digital Fallbacks

Reference: easyJet: check-in and boarding passes

Compare: Booking reference

An identifier used to retrieve a reservation in an airline's or travel seller's system, also called a record locator or confirmation code. The relevant carrier may use a different reference from an agency or partner. Keep it with the trip details, and distinguish it from a ticket number and the boarding pass issued for a flight.

Guide: Airline Check-In: Booking References, Boarding Passes, and Digital Fallbacks

Reference: American Airlines: finding and managing a reservation

A print mode intended to cover the sheet to its edges without an unprinted margin. Some printers enlarge the image slightly beyond the paper boundary, cropping edge detail. Check supported paper sizes and the expansion setting, preview the crop, and keep important content away from the edges; matching aspect ratios alone may not preserve every pixel.

Guide: Print Photos from Your Phone: Files, Crops and Connections

Reference: Epson: borderless printing and image expansion

Compare: Aspect ratio, PPI, Inkjet printing

Business Process Execution Language, an XML-based language for describing business processes that interact with web services. It addresses the coordination of service activities rather than the visual layout of an application.

Related coverage: BPEL: Understand and Assess a Legacy Orchestration Process

Binary Runtime Environment for Wireless, Qualcomm's platform for applications on supported mobile devices. It is useful terminology when reading about the software and distribution systems of earlier mobile phones.

Related coverage: Qualcomm BREW: How Carrier-Delivered Phone Apps Worked

A general term for high-capacity communications access. Regulatory speed thresholds vary by jurisdiction and date; use a service's stated download and upload rates for a specific comparison.

A unit of digital information normally consisting of eight bits. Storage and file sizes are commonly expressed in bytes, while connection rates commonly use bits per second. Uppercase B denotes bytes in unit symbols.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: NIST: bits, bytes and prefixes

Compare: RAM, SSD, Bit

Adjusting a device toward a specified operating state, such as a display's white point and luminance. Profiling then describes how the device behaves in that state; stable viewing conditions support meaningful comparisons.

Read the guide: Color Management for Digital Art and Printing

Reference: International Color Consortium: profiles

Compare: Profiling (color), Color space, Embedded profile

Text synchronized with audio or video that conveys speech and relevant sound information, including speaker identification when needed. Closed captions can be switched on or off; open captions remain visible. Review timing and accuracy, including meaningful sounds, since dialogue-only translations may omit information needed to understand the media.

Guide: Website Accessibility Check: A Practical First Audit

Reference: W3C: captions and subtitles

Compare: Audio stream, Reading order

A network access page that asks a visitor to complete a step, such as signing in or accepting service terms, before gaining broader network or internet access. Joining the Wi-Fi network and completing its portal are separate stages. Confirm the provider’s official instructions before entering account or payment information.

Guide: Airport Wi-Fi: Find the Official Network and Get Connected

Reference: Apple: joining captive Wi-Fi networks

Compare: SSID, Wi-Fi, Authentication

A description applied to equipment intended for telecommunications-provider operation. Establish the actual requirements for availability, redundancy, maintenance and support instead of treating the phrase as a universal certification.

Column address strobe latency: the number of memory clock cycles between a DRAM read command and the first requested data becoming available. Usually labeled CL, it is one part of memory-access delay. Compare both CL and operating transfer rate: DDR5-6000 CL30 has a 10-nanosecond CAS component, not a guaranteed 10-nanosecond total system memory latency.

Guide: RAM Upgrades: Capacity, Compatibility, and Stable Settings

Reference: Corsair: CAS latency and memory timings

Compare: DDR, MT/s, RAM

Aluminum or an aluminum alloy shaped by introducing molten metal into a mold and allowing it to solidify. The process can produce detailed furniture components. A finished item may combine cast and extruded parts; evaluate its alloy, joints, protective finish and care instructions alongside the casting description.

Guide: Cast Aluminum Patio Furniture: Construction, Finish, and Upkeep

Reference: The Aluminum Association: casting and extrusion

Sending or directing media playback from one device to a compatible receiver. Depending on the system, the receiver may fetch the stream itself or receive it from the controlling device; supported services and networks matter.

Read the guide: Internet Radios: Choose a Receiver, Find Stations, and Set It Up

Carbon capture and storage: capturing carbon dioxide, transporting it and storing it in a suitable geological formation. Evaluating a project requires following the whole chain and identifying the emissions that remain.

Related coverage: Carbon Capture and Storage: Evaluate the Whole Project

Consumer Electronics Control: HDMI signaling that lets compatible devices exchange control commands, such as power, input selection or volume. Manufacturers use different feature names and support different actions. A TV remote controlling a soundbar through CEC demonstrates a control function; the return-audio connection is a separate ARC/eARC function.

Guide: HDMI Connections: Match Ports, Cables, and Features

Reference: Sony: HDMI-CEC control functions

Compare: HDMI, Audio Return Channel (ARC and eARC)

Consumer electronics: electronic devices intended primarily for individual or household use. In product and trade-show reporting this abbreviation names a sector; the CE conformity marking is a different use of the letters.

Related coverage: CES 2010 exhibitors

A mobile telephone that communicates through a cellular radio network. Frequency bands and supported network generations vary by handset and carrier, so a single frequency range cannot describe every cell phone.

Related coverage: Telephone Guides: Find Help by Task or Topic

The frequency span used by a radio channel, commonly stated in megahertz for Wi-Fi. A wider channel can support a higher data rate when compatible devices and conditions allow, while occupying more spectrum and reducing opportunities to reuse separate channels nearby. Evaluate width together with interference, client support and measured throughput under the expected workload.

Guide: Wi-Fi Channel Planning: Balance Width, Reuse and Airtime

Reference: Cisco Meraki: channel bonding and width tradeoffs

Compare: Airtime, Bandwidth (network capacity), Throughput

A value calculated from data to help detect changes. Comparing a file’s checksum with a trusted earlier value can help verify a copy. The comparison must use the same algorithm; matching values do not establish that the original file was safe, complete or the intended recording.

Guide: Panasonic P2: Copy, Verify and Preserve Camera Cards

Reference: NIST: checksum

Compare: Backup, Restore (data)

A map that shades geographic areas according to a statistic for each area, such as a district's percentage of tree cover. The legend connects colors to values or classes. Check the statistic's denominator, geographic boundaries and classification method: a uniform shade summarizes an area while local conditions within it can vary.

Guide: Map Colors with ColorBrewer: Choose, Classify, and Check

Reference: Esri: graduated colors and choropleth mapping

Compare: Class interval (mapping), Sequential color scheme, Diverging color scheme

A separation method in which a mobile phase carries a mixture through or over a stationary phase. Components interact differently with the phases and therefore move differently through the system. Chromatography can separate substances before detection by mass spectrometry or another detector; assessing an identity also requires appropriate reference evidence and method checks.

Guide: Mass Spectrometry: Read the Signal and Understand the Evidence

Reference: Teledyne LABS: mobile and stationary phases

Compare: Retention time (chromatography), Mass spectrometry

The holding mechanism that secures a drill bit or other compatible accessory. A common drill chuck closes three jaws around the accessory's shank, using a key or a keyless tightening mechanism. Check the chuck's size range and interface; the tool's permitted drilling capacity and operating mode are separate compatibility requirements.

Guide: Cordless Drills: Choose the Tool and Set It Up for the Job

Reference: Bosch: drill shanks and chuck interfaces

Compare: Shank (tool)

In ice-cream making, agitating the mixture while it partly freezes, incorporating air and scraping frozen material from the cooling surface. This produces a softer mixture than the finished scoopable dessert. Subsequent hardening in a freezer freezes more of the remaining water; it is a separate stage, not simply more churning.

Guide: Homemade Ice Cream: Base, Churning and Texture

Reference: University of Guelph: freezing and whipping ice cream (PDF)

Compare: Emulsion, Creaming (baking)

Communication that establishes a dedicated connection or reserved circuit resources for a session. Traditional telephone networks used this approach; the particular system determines how resources are allocated.

The compressive force that holds the parts of a joint together. In a tightened bolted joint, tension in the bolt produces compression in the joined materials. Applied torque is an indirect way to establish this force: friction and assembly conditions affect the result. Follow the exact joint's specified tightening method and conditions.

Guide: Torque Wrenches: Specifications, Units and Controlled Tightening

Reference: Atlas Copco: clamping force and bolt preload · Nord-Lock: torque, friction and preload

Compare: Torque

A range of numerical values assigned to one category in a map legend. Class breaks mark the boundaries between ranges. Equal intervals use equal numeric widths; quantiles aim for similar numbers of observations per class. Specify which boundary values belong in each class, and retain consistent breaks when colors must remain comparable across maps.

Guide: Map Colors with ColorBrewer: Choose, Classify, and Check

Reference: Esri: map data classification methods and class breaks

Compare: Choropleth map, Sequential color scheme, Diverging color scheme

An unthreaded hole sized to let the specified fastener pass through a part without its threads engaging that part. In a screwed wood joint, clearance through the outer piece helps the screw draw the pieces together. Use the required fit and dimensions for the actual fastener and joint, separately from any pilot hole.

Guide: Drill Bits: Match the Material, Hole and Drill

Reference: Bosch: screw-shank clearance and joint assembly (PDF)

Compare: Pilot hole, Clamp force

Tools that present relevant knowledge and patient-specific information to support care decisions. Examples include alerts, reminders and reference information; clinical judgment and the quality of the underlying information remain important.

Reference: HealthIT: clinical decision support

The limiting of image values at the bright or dark end of a recording or processing range, which can erase distinctions in that region. Clipping may affect individual color channels as well as overall brightness. Check the image, histogram and warnings together, and distinguish a clipped preview from information still retained in the source file.

Guide: Landscape Photography: Plan the Frame, Light, and Exposure

Reference: Nikon: highlight warnings and image tones

Compare: Histogram (imaging), Dynamic range (imaging), RAW image file

An image sensor built using complementary metal-oxide-semiconductor technology and associated readout circuitry. Sensor dimensions, pixel design and readout behavior help explain image quality beyond the CMOS label alone.

Read the guide: CMOS Image Sensors: Size, Pixels, Noise and Shutter Readout

Reference: Canon: image sensors

A method or implementation for encoding and decoding an audio or video stream. Codecs determine how the media is represented and may use lossy or lossless compression. A container holds those streams; an MP4 filename alone does not identify every codec a player must support.

Guide: Lossless Video Codecs: Masters, Editing and Viewing Copies

Reference: MDN: media containers and codecs

Compare: Container (media file), PCM (audio), APC (adaptive predictive coding)

Standard deviation divided by the mean, often multiplied by 100 to report a percentage. For example, a fictional mean volume of 100 µL with a standard deviation of 1 µL has a CV of 1%. It compares relative spread for measurements with a meaningful zero; values become unstable near a zero mean and are undefined at zero.

Guide: Pipetting: Improve Accuracy, Precision, and Repeatability

Reference: NIST: coefficient of variation and its limits

Compare: Standard deviation, Repeatability (measurement), Percentage point

A sleeve-shaped clamping component that tightens around a tool shank. In a router, the collet holds a bit of the specified shank diameter, unlike the adjustable jaws of a typical drill chuck. Match the router's approved collet and bit: a 1/4-inch shank is 6.35 mm, so it is not interchangeable with a 6 mm shank.

Guide: Router Bits: Match the Profile, Shank and Cut

Reference: Freud: routing-tool clamping requirements (PDF)

Compare: Shank (tool), Chuck, Runout

A defined system for representing colors with numerical values and a specified interpretation. Names such as sRGB identify particular spaces; the same numeric RGB values can describe different colors in different spaces.

Read the guide: Color Management for Digital Art and Printing

Reference: International Color Consortium: profiles

Compare: Calibration (color), Profiling (color), Embedded profile

Video carried as separate signal components. Consumer analog YPbPr commonly uses three video cables; audio is separate. Check the signal labels because similar-looking connectors can carry different types of information.

Read the guide: How to Play DVDs Today: TVs, Computers, Consoles, and Portable Players

An analog video signal combining picture information into a single signal path, commonly using a yellow RCA connector on consumer equipment. Audio uses separate connections; the connector shape alone does not identify every signal it can carry.

Read the guide: How to Play DVDs Today: TVs, Computers, Consoles, and Portable Players

The arrangement of forms, colors, spaces and other visual elements in an artwork. Looking at balance, direction and relationships between figures helps explain how the arrangement guides attention.

Read the guide: How to Look at Seurat’s La Grande Jatte

Reference: Art Institute of Chicago: La Grande Jatte

Compare: Pointillism, Pigment

Obtaining consistent computational results using the same input data, methods, code and analysis conditions. Preserving versions, dependencies and processing steps helps others rerun the analysis. This checks the computational result; evaluating the underlying assumptions and collecting independent new observations address additional questions about the scientific conclusion.

Guide: E-Science: Build a Reproducible Research Workflow

Reference: National Academies: reproducibility and replicability

Compare: FAIR principles, Metadata, Repeatability (measurement)

Malware that reproduces by inserting or attaching its code to another program or host object. Running or opening the affected host can help it spread; other malware may spread through different mechanisms.

Read the guide: Anti Virus and Malware: Protection, Recovery, and Outbreak Lessons

Reference: NIST: virus terminology

Compare: Malware, Ransomware, Quarantine (security software)

A self-contained program that can replicate and spread between systems, commonly across a network. A worm can propagate independently of a host program; individual worms use different entry and spread mechanisms. Sasser, for example, spread through vulnerable network services. Identify the actual route when deciding which patches and containment measures apply.

Guide: Sasser: How a Worm Spread Without an Email Attachment

Reference: NIST: worm

Compare: Malware, Computer virus, Software patch

A situation in which the available observations cannot separate the effects of two or more influences. In an experiment, testing every A specimen on Monday and every B specimen on Tuesday entangles treatment with day. More readings in that same arrangement preserve the ambiguity; the design needs comparisons that allow the effects of interest to be distinguished.

Guide: Research Design Tools: Turn a Question into a Testable Experiment · Causal Inference

Reference: NIST: confounding of experimental effects

Compare: Blocking (experiments), Randomization (experiments), Experimental unit

A file structure that holds media streams and associated information, such as timing, subtitles and metadata. MP4, Matroska and QuickTime are examples. The container is the wrapper; the codecs describe how its audio and video are encoded. Playback support depends on the actual combination, not just the file extension.

Guide: Lossless Video Codecs: Masters, Editing and Viewing Copies

Reference: MDN: media container formats

Compare: Codec, MIME

A comparison of the relative luminance of two colors, commonly text and its background, expressed as a ratio such as 4.5:1. WCAG 2.2 uses 4.5:1 for ordinary text under its Contrast (Minimum) criterion, with specified exceptions. Check the colors actually displayed together; passing this measure covers one aspect of readability.

Guide: Website Accessibility Check: A Practical First Audit

Reference: W3C: Contrast (Minimum)

Compare: Reflow (content), Color space

The network functions that establish and maintain information used to direct traffic, such as routing decisions. Packet forwarding applies that information in the data plane.

Combining services such as voice, video and data on a shared communications infrastructure. Capacity, service quality and operational responsibilities still need to be defined for each service.

A framework that connects coordinate values to positions through a coordinate system and a reference datum or frame. It specifies information such as axis order, direction and units. Geographic coordinates and projected map coordinates use different frameworks; identify the source and destination systems before combining or transforming location data.

Guide: Geocoding: Turn Addresses into Coordinates You Can Check

Reference: OGC: referencing by coordinates

Compare: Geographic coordinates, Map projection, Geocoding

Beating softened fat, commonly butter, with sugar to incorporate small air pockets before other ingredients are added. Those pockets help establish the texture of many cakes and cookies and can expand during baking. Melted butter does not hold this aerated structure in the same way; use the consistency and mixing cues specified by the recipe.

Guide: Cookies: Control Spread, Texture and Baking

Reference: King Arthur Baking: creaming butter and sugar

Compare: Leavening, Emulsion

Customer relationship management: the practices and software used to organize interactions with customers and prospective customers. A CRM record may connect contact details, service history and sales activity.

Related coverage: CRM for Small Teams: Choosing a System and Making It Useful

Filtering that directs different frequency ranges to different drivers or speakers. A loudspeaker can contain a crossover network; an AV receiver can also use a crossover setting to divide bass between main speakers and a subwoofer. The frequency, filter behavior and routing must suit the particular system.

Guide: AV Receiver Setup: Inputs, Speakers, and Listening Modes

Reference: Yamaha: receiver crossover frequency and routing

Compare: AV receiver, Speaker impedance

A thin first layer of frosting that holds loose cake crumbs in place and provides a base for the final coating. Apply it to a cooled cake and let it set as appropriate for the frosting before finishing. Some cake or crumbs may remain visible through this preparation layer; its purpose is to support the later finish.

Guide: Cake Decorating: Level, Fill, Crumb-Coat and Finish

Reference: Wilton: crumb-coat purpose and preparation

A sanitization technique that makes encrypted data inaccessible by sanitizing the cryptographic keys needed to decrypt it. Its effectiveness depends on the encryption implementation, coverage of the target data and elimination of recoverable key copies. A device-specific, verified procedure is essential; changing a login password alone does not establish that the data has been sanitized.

Guide: Computer Disposal: Reuse, Data Sanitization, and Recycling

Reference: NIST: cryptographic erase and key sanitization (PDF)

Compare: Data sanitization, Recovery key (device encryption)

A solid whose atoms are arranged in a repeating ordered structure. Its visible faces can reflect that internal order, but a mineral grain can still be crystalline even when distinct external faces are absent.

Read the guide: Rocks and Minerals: A Guide to Observing and Understanding Them

Reference: National Park Service: minerals

Coarse wavelength-division multiplexing: carrying several optical channels at different, relatively widely spaced wavelengths on a fiber. Channel plans and the supported equipment determine which signals can share the link.

Related coverage: CWDM: Coarse Wavelength Division Multiplexing

Digital Audio Broadcasting, a family of terrestrial digital-radio standards. A receiver's supported standard, including DAB or DAB+, and the broadcasts available in its region determine compatibility.

Related coverage: DAB and DAB+ Radio: Compatibility, Coverage, and Retuning

Conversion from a digital representation to an analog signal. For example, an audio digital-to-analog converter produces an electrical waveform from digital audio samples.

Direct-attached storage: storage connected directly to its host computer rather than reached through a storage network. Internal drives and directly connected external drives are common examples. DAS describes the connection arrangement; it does not specify the drive technology, file system or RAID configuration. The host may separately share files from that storage over a network.

Guide: Disk Storage Systems: Match Architecture to Workload

Reference: IBM: data storage architectures

Compare: Block storage, NAS, RAID

A process for making access to selected data on storage media impractical within a specified level of effort. The appropriate method depends on the medium, data sensitivity and intended reuse or disposal. Choose a documented procedure and verify its outcome; removing a filename alone can leave recoverable data behind.

Guide: Computer Disposal: Reuse, Data Sanitization, and Recycling

Reference: NIST: media sanitization methods and validation (PDF)

Compare: Cryptographic erase, File system, SSD

A logarithmic power unit referenced to one milliwatt: 0 dBm equals 1 mW and 10 dBm equals 10 mW. Negative readings represent powers below 1 mW; −60 dBm is stronger than −80 dBm. Read whether a specification describes transmitted power, received power or receiver sensitivity, and compare it under the stated operating conditions.

Guide: Bluetooth Transceivers: Radio Range, Antennas, and Link Budgets

Reference: Rohde & Schwarz: decibels and referenced power levels (PDF)

Compare: RSSI, Signal-to-noise ratio, Watt

Digital Congress Network, Bosch's name for a conference-system family. In this context the acronym refers to equipment for meeting participation and interpretation, rather than a general networking protocol.

Related coverage: Conference Interpretation Systems: Plan a Multilingual Meeting

Double data rate: a memory signaling method that transfers data on both the rising and falling edges of a clock cycle. DDR memory generations, such as DDR4 and DDR5, also define different interfaces and operating requirements. Match the generation and module type to the system's documentation, then compare capacity, transfer rate and timings.

Guide: RAM Upgrades: Capacity, Compatibility, and Stable Settings

Reference: Kingston: DDR memory signaling, data rates and compatibility (PDF)

Compare: RAM, MT/s

Removing or transforming identifying information to reduce the risk that data can be linked to a person. The required methods and the remaining risk depend on the data and the applicable framework, such as HIPAA for U.S. health information.

Reference: HHS: de-identifying health information

The range of distances in a scene that appears acceptably sharp at a chosen focus setting and viewing condition. Aperture, focal length and subject distance influence it. For otherwise comparable settings, a smaller lens opening usually increases this range. Review important near and far details at the intended display or print size.

Guide: Landscape Photography: Plan the Frame, Light, and Exposure

Reference: Nikon: aperture and depth of field

Compare: Aperture, Shutter speed

Removing mineral scale deposited on equipment, such as a kettle’s heating surfaces. Scale can slow heating and affect operation. Use the appliance’s approved product, method and rinsing instructions, with frequency guided by its manual and buildup. Descaling addresses mineral deposits; disinfection and repairs address different problems.

Guide: How Fast Should a Kettle Boil? Comparing Time and Water Volume

Reference: OXO: kettle troubleshooting and descaling instructions

Compare: Hard water

Differential GPS: improving GPS positioning with corrections derived from a reference receiver at a known location. The correction method, distance from the reference and receiving equipment affect the result.

Related coverage: Differential GPS: DGNSS, RTK, PPP, and Correction Services

Dynamic Host Configuration Protocol: a client-server protocol that supplies network configuration, commonly including an IP address and related settings. In typical IPv4 networks an address can be leased for a limited time. Receiving configuration, resolving a name through DNS and reaching the intended service are separate stages to check during troubleshooting.

Guide: Wireless Infrastructure: Trace an Outage Across the Service

Reference: RFC 2131: Dynamic Host Configuration Protocol

Compare: IP, DNS, Router

A mathematical framework that bounds how much an analysis can reveal about the participation of an individual in a dataset. Its protection depends on the mechanism and privacy parameters, not simply on describing data as anonymous.

Reference: NIST: differential privacy

The spreading and interference of waves as they pass an aperture or encounter an edge or obstruction. In a telescope, diffraction spreads a point source's light into a pattern and sets an ideal limit on detail. That angular scale grows with wavelength and shrinks with aperture diameter; atmospheric blur and detector sampling impose additional constraints.

Guide: Infrared Telescopes: Wavelengths, Thermal Background and What Images Reveal

Reference: NASA Webb: how diffraction shapes telescope images

Compare: Angular resolution, Adaptive optics, Spectral band

A signed electronic record that binds a public key to a named subject, such as a server, user or device. Systems check the issuer’s trust, signature, validity and permitted use when accepting it. A certificate supports identity checks in protocols such as TLS; possession of the corresponding private key must also be demonstrated.

Guide: Wireless LAN Authentication: 802.1X, RADIUS and EAP Methods

Reference: RFC 5280: public-key certificates and validation

Compare: TLS, EAP-TLS, Authentication

A digital representation of surface elevations relative to a stated reference, commonly arranged as a grid. Laser ranging, stereo imagery and other measurements can supply its data. Read the product's units, reference surface, sampling and interpolation information before calculating relief or slope; grid spacing alone does not establish the detail or accuracy supported.

Guide: Moon Topography: How to Read Lunar Terrain Maps

Reference: NASA PDS Geosciences: lunar altimetry tracks, grids and elevation scaling

Compare: Vertical exaggeration, Ground sample distance, Coordinate reference system

Dual in-line memory module: a circuit board carrying memory chips and contacts for a matching socket. Memory generation, module type and system support must agree before a module can be used.

Related coverage: Fully Buffered DIMMs: Identify Legacy Server Memory and Check Compatibility

The viewfinder adjustment that helps bring its display or markings into focus for the viewer's eyesight. Set it while looking at the viewfinder information; the camera lens separately focuses the photographed subject.

Read the guide: Electronic Viewfinders: See Clearly and Judge the Preview

Reference: Canon: viewfinder adjustment

Compare: EVF (electronic viewfinder)

Completing a recorded optical disc’s required playback information so compatible players or drives can use it. DVD camcorders may require finalization according to the disc type and recording mode. Follow the recorder’s procedure and power instructions; playback compatibility and the ability to add recordings afterward depend on the medium and equipment.

Guide: DVD Camcorders: Transfer Recordings from 8 cm Discs

Reference: Canon: finalizing camcorder discs and compatible playback (PDF)

Compare: DVD, Backup

A file representing a disc’s contents and organization in a particular image format. For optical-media preservation, it can retain a disc-level structure beyond a single extracted movie file. Record the imaging format and tool, preserve the original medium, and verify readable titles or files; an image cannot recover data that the drive could not read.

Guide: DVD Camcorders: Transfer Recordings from 8 cm Discs

Reference: Apple: creating images from disks and connected devices

Compare: Disc finalization, DVD, Backup

A color scheme with two contrasting directions extending from a meaningful central value or class, such as losses and gains around zero. Lightness often emphasizes increasing distance from that center. Choose the center from the subject being mapped, and make the legend's colors and boundaries reflect that choice; the observed range's midpoint may be arbitrary.

Guide: Map Colors with ColorBrewer: Choose, Classify, and Check

Reference: ColorBrewer: choosing a meaningful center for diverging schemes

Compare: Sequential color scheme, Class interval (mapping), Choropleth map

DomainKeys Identified Mail: an email signing mechanism that associates a signing domain with a message. A receiver uses the domain’s published public key to verify the signature over covered message content. The signing domain can differ from the visible author’s domain; the signature provides an integrity and domain check while the message itself remains readable.

Guide: Email Sender Authentication: SPF, DKIM, DMARC, and Their Limits

Reference: RFC 6376: DomainKeys Identified Mail signatures

Compare: SPF, DMARC, Digital certificate

Domain-based Message Authentication, Reporting, and Conformance: a way for an email domain owner to publish handling preferences and request authentication reports. A pass requires SPF or DKIM to pass with its authenticated domain aligned to the visible From address’s domain. This validates authorized domain use; readers still need to assess the message’s requested action.

Guide: Email Sender Authentication: SPF, DKIM, DMARC, and Their Limits

Reference: RFC 9989: DMARC domain alignment, policy and reporting

Compare: SPF, DKIM, Email spoofing

Digital Multimedia Broadcasting, a family of systems for transmitting digital audio, video and data to compatible receivers. The relevant terrestrial or satellite system and regional service determine what equipment can receive.

Related coverage: DMB Phones: Broadcast Television and the Samsung B200

Domain Name System: a distributed naming system that returns records associated with domain names, including address records. A DNS answer and successful access to the named service are separate steps.

Read the guide: OSI Layers in Practice: Follow a Connection, Find a Fault

Reference: Domain names (RFC 1034)

A change in observed wave frequency associated with relative motion between a source, reflector and observer. Radar uses the shift in returning signals to infer motion toward or away from the instrument. The result depends on viewing direction, so a speed measured along the radar’s line of sight can differ from the target’s full speed.

Guide: Bushnell Radar Guns: Models, Setup, and Reliable Speed Readings

Reference: National Weather Service: Doppler radar and motion

Compare: Radar reflectivity

Digital particle image velocimetry: estimating fluid motion by comparing recorded images of particles in the flow. The measurements describe motion in the observed region under the experiment's imaging and timing conditions.

Related coverage: Water flow diagnostics

Digital rights management: technologies used to control access to or use of digital content. A file's format and a user's permission or license are separate parts of whether it can be played or opened.

Related coverage: DRM and Media Portability: Files, Licenses and Playback Rights

Dichotomous sampler: an air-sampling instrument that separates collected particles into two size fractions. Its size cut and measurement method must be stated with the resulting particulate measurements.

Reference: EPA: dichotomous sampling (PDF)

Digital signal: information represented using discrete values or symbols. A system's encoding determines how those symbols represent measurements, text or other data.

Dual screen: a device or arrangement with two displays. The abbreviation describes the display arrangement in this context, rather than a communications standard.

Dye-sensitized solar cell: a photovoltaic cell in which a dye absorbs light as part of the process that generates electrical current. Output and durability depend on the cell design and operating conditions.

Related coverage: Dye-sensitized solar cell

Diagnostic trouble code: a code recorded by a vehicle's diagnostic system when it detects a condition outside its expected limits. Read the code's description, status and vehicle context, then use the applicable diagnostic procedure to investigate. A code identifies a detected condition; confirming the failed component or circuit requires further evidence.

Guide: Automotive Diagnostics: From a Reported Symptom to a Verified Repair

Reference: OBD Auto Doctor: diagnostic trouble codes

Compare: OBD, Freeze-frame data (vehicle)

For welding equipment, the proportion of a stated interval during which the machine can weld at a specified output without overheating. A hypothetical 60% rating over ten minutes means six minutes welding and four minutes cooling. Read the rating with its current, voltage, ambient conditions and the manual's cooling requirements.

Guide: Engine-Driven Welders: Read Welding and Generator Ratings

Reference: Miller: welding duty cycle and operating conditions

An optical-disc format used for video and data. A player must support the disc type, recording format and, where relevant, video region; DVD, Blu-ray and Ultra HD Blu-ray are distinct formats.

Read the guide: How to Play DVDs Today: TVs, Computers, Consoles, and Portable Players

A heat-driven printing process that transfers dye to a compatible receiving surface. Compact photo printers using this method commonly require a matched ink and paper system and may add a protective overcoat. Check the exact printer’s supported supplies, print sizes and handling instructions when comparing its workflow with a photo inkjet.

Guide: Photo Printers: Choose a Method and Plan the Real Cost

Reference: Canon: SELPHY dye-sublimation printing and media specifications

Compare: Inkjet printing, Borderless printing, PPI

The range between the strongest and weakest signals an imaging system can usefully distinguish under stated conditions. In photography it is often expressed in stops; exposure, noise criteria and processing affect the measurement.

Read the guide: CMOS Image Sensors: Size, Pixels, Noise and Shutter Readout

Reference: Canon: image sensors

Extensible Authentication Protocol: a framework that carries exchanges for several network authentication methods. The selected method determines the credentials and security properties, such as certificates with EAP-TLS. In an enterprise Wi-Fi setup, an access point can relay the exchange to an authentication server; check the configured method and its requirements when diagnosing a failed join.

Guide: Wireless LAN Authentication: 802.1X, RADIUS and EAP Methods

Reference: RFC 3748: the EAP framework and roles

Compare: EAP-TLS, RADIUS, Authentication

An Extensible Authentication Protocol method that uses TLS and certificates for mutual authentication between a client and authentication server. It is used in managed network access, including enterprise Wi-Fi. A working deployment needs client enrollment, trusted server identity and certificate renewal and revocation handling; the method is one choice within the broader EAP framework.

Guide: Wireless LAN Authentication: 802.1X, RADIUS and EAP Methods

Reference: RFC 9190: EAP-TLS with TLS 1.3

Compare: EAP, TLS, Digital certificate

Error-correcting code, or the circuitry implementing it, used to detect and correct specified data errors. In memory, the supported error patterns depend on the code and system design; ECC does not guarantee recovery from every fault.

Related coverage: DDR SDRAM: Transfers, Refresh, and Legacy Compatibility

Electronic health record: a digital collection of information used in a person's care, such as clinical notes, medications and test results. Systems need shared formats and appropriate access arrangements to exchange that information usefully.

Reference: HealthIT: electronic health records

The U.S. Energy Information Administration, a source of energy statistics, analysis and projections. When using its data, keep the series, units, observation period and release date with the number.

Related coverage: U.S. Oil Production: Read Trends, Revisions and Forecasts

A point's height above or below a specified reference ellipsoid, measured along a line perpendicular to that ellipsoid. GNSS positions commonly yield this geometric height, written h. Converting it to an orthometric height requires compatible reference systems and a geoid model; keep the height type and reference metadata with the coordinate.

Guide: GPS Surveying: Reference Systems, Field Records, and Quality Checks

Reference: NOAA NGS: ellipsoidal heights and height conversion

Compare: Geoid, Orthometric height, Coordinate reference system

The warm phase of ENSO, involving above-average sea-surface temperatures in the central and eastern tropical Pacific and associated atmospheric changes. Equatorial trade winds typically weaken. El Niño can alter seasonal rainfall and temperature patterns around the world, but it does not mean every place becomes warmer or experiences the same weather in every event.

Guide: La Niña Explained: ENSO, RONI and Seasonal Outlooks

Reference: NOAA National Weather Service: El Niño

Compare: ENSO, La Niña

Falsifying an email’s apparent sender information so it seems to come from another person or organization. A forged display name or address can mislead a recipient even when the named person’s account remains secure. Distinguish the identity shown in the message from evidence of an actual account login or compromise.

Guide: Bagle.C: Forged Senders, Harvested Addresses, and Misleading Clues

Reference: Microsoft: anti-spoofing protection

Compare: Phishing, Authentication

Color-profile information saved inside an image or document to identify how its color values should be interpreted. Software can use it when displaying, converting or printing the file; assigning a profile and converting values are different operations.

Read the guide: Color Management for Digital Art and Printing

Reference: International Color Consortium: profiles

Compare: Calibration (color), Profiling (color), Color space

A mixture in which tiny droplets of one liquid are dispersed through another liquid that it does not readily mix with. Shaking oil and vinegar creates a temporary emulsion that can separate again. Mixing technique and ingredients such as mustard can help a dressing remain dispersed longer; follow the recipe's method and serving guidance.

Guide: Culinary Vinegar: Choose a Type and Balance a Dish

Reference: Escoffier teaching text: emulsions and vinaigrettes (PDF)

El Niño-Southern Oscillation: a recurring pattern of linked ocean and atmospheric changes in the tropical Pacific. It includes the warm El Niño phase, cool La Niña phase and neutral conditions. Changes in circulation can alter seasonal temperature and rainfall probabilities far beyond the Pacific; ENSO is one influence on an outlook, not a local daily forecast.

Guide: La Niña Explained: ENSO, RONI and Seasonal Outlooks

Reference: NOAA National Weather Service: ENSO and its phases

Compare: El Niño, La Niña, Forecast cone

École polytechnique fédérale de Lausanne, a Swiss federal institute of technology. The abbreviation identifies the institution, including in reports about its research and technology licensing.

Related coverage: G24i

A family of local-network technologies standardized in IEEE 802.3. Copper and fiber versions support different speeds and distances; Ethernet names the network technology rather than a single connector or cable category.

Read the guide: IEEE 802 Explained: Read Ethernet, Wi-Fi, and VLAN Specifications

Reference: IEEE 802.3 Ethernet

An eyepiece display showing an electronic image from a camera. Exposure preview and focus aids can help compose a photograph; the diopter adjustment sharpens the photographer's view of the display without changing lens focus.

Read the guide: Electronic Viewfinders: See Clearly and Judge the Preview

Reference: Canon: viewfinder adjustment

Compare: Diopter adjustment

Extended File Allocation Table: a file system designed to support large files and storage volumes, commonly used for removable storage. It is a useful interchange option for compatible systems. Check support on the particular camera, recorder, television or computer before formatting, and retain a separate copy of any existing files.

Guide: Portable Storage: SSDs, Hard Drives, Connections, and Backups

Reference: Microsoft: exFAT file system specification

Compare: File system, Backup

The entity independently assigned to an experimental treatment or condition, such as a person, plot or separately prepared specimen. Identify it before counting the sample size. Ten readings from one treated specimen describe repeated observations on that specimen; they do not create ten independently treated experimental units.

Guide: Research Design Tools: Turn a Question into a Testable Experiment

Reference: NIST: experimental-design terminology

Compare: Randomization (experiments), Blocking (experiments), Confounding

A setting that asks the camera to make its automatic exposure result brighter or darker than its metered suggestion. Positive compensation generally brightens and negative compensation darkens. The camera adjusts the controls available in the selected mode. This changes the exposure decision; turning up the screen brightness only changes how the display looks.

Guide: Better Phone Photography: Override Auto Exposure on iPhone and Android

Reference: Nikon: exposure compensation

Compare: Shutter speed, Dynamic range (imaging)

The light reaching the recording surface during capture, determined by scene illumination, the lens opening and exposure time. Adjusting those factors changes the captured light. ISO and image processing also affect the rendered brightness, so a brighter preview by itself does not show that more light was recorded.

Guide: Better Phone Photography: Override Auto Exposure on iPhone and Android

Reference: Nikon: the controls involved in exposure

Compare: Aperture, Shutter speed, ISO (photography), Exposure compensation

XML entity declarations that refer to content outside the document. A parser that resolves untrusted external references can expose files or make unwanted network requests; secure configuration controls which resolution features are enabled.

Read the guide: Web Service Security: Access, XML Parsing, and Resource Limits

Reference: OWASP: external entity prevention

Switching service or traffic to an alternative resource when the active one fails or becomes unsuitable. A multi-WAN router can direct traffic to a backup internet connection after a health check detects trouble. Detection time, address changes and application behavior affect continuity, so verify what happens to an active call or session during a controlled test.

Guide: Wireless Bandwidth Aggregation: Bonding, Balancing and Failover

Reference: Peplink: backup links and failover behavior

Compare: Load balancing, Link bonding, Availability

Guidelines for making digital research resources Findable, Accessible, Interoperable and Reusable. They emphasize persistent identifiers, useful metadata, shared formats and vocabularies, provenance and clear reuse conditions, including machine-readable information. Accessible resources can require authentication and authorization: FAIR supports documented access arrangements as well as openly downloadable data.

Guide: E-Science: Build a Reproducible Research Workflow

Reference: GO FAIR Foundation: FAIR Guiding Principles

Compare: Metadata, Interoperability, Computational reproducibility

A result that reports a target condition when that condition is absent. A spam filter marking a legitimate message as spam is a false positive. A false negative misses a condition that is present. Define the target and inspect examples of both errors when judging a filter’s usefulness.

Guide: SpamSquelcher and the Challenge of Accurate Spam Filtering · Confusion Matrix (AI Glossary)

Reference: NIST: false positive

Compare: Antivirus, Phishing

Fully Automated Storage Tiering, EMC's name for technology that moved data between storage tiers according to policy and activity. Historical product claims should be read with the specific platform and software release.

Related coverage: EMC FAST fully automated storage tiering

The ability to continue a specified service when a component or operation fails. Its extent depends on the failure types covered and on whether redundant parts share a common vulnerability.

Training a shared machine-learning model by exchanging model updates across devices or organizations while the training data remain with their holders. Additional controls are needed to address information that updates themselves may reveal.

Reference: NIST: federated learning

Feline leukemia virus, a retrovirus that infects cats and can affect their immune and blood-forming systems. Veterinary testing is needed to interpret an individual cat's infection status.

Related coverage: Cat Health Problems: First Visits, FIV/FeLV Tests, and Home Notes

Reference: Cornell: feline leukemia virus

Fast Healthcare Interoperability Resources, HL7's framework for exchanging health information through defined resources and interfaces. An implementation must identify its FHIR version and applicable profiles to establish compatibility.

Reference: HL7 FHIR summary

Frequency-hopping spread spectrum: transmitting by moving among radio frequencies according to an agreed sequence. The hopping pattern and channel use belong to the particular radio system.

Related coverage: RF Modems: Plan and Test a Serial Telemetry Link

Flight-initiation distance: the distance between an approaching disturbance and an animal when the animal begins to flee. The species, approach and surrounding conditions matter when comparing observations.

Related coverage: HID lights high intensity discharge lighting

The rules and structures a system uses to organize, name, store and retrieve files on a storage volume. Examples include exFAT, NTFS and APFS. Check read and write support on every intended device before choosing a format; the drive’s connector and physical storage technology describe separate compatibility requirements.

Guide: Portable Storage: SSDs, Hard Drives, Connections, and Backups

Reference: Microsoft: how file systems organize stored files

Compare: exFAT, SSD, USB-C

A control that permits or blocks network traffic according to rules. A firewall may run on a device or at a boundary between networks. Its coverage depends on where traffic passes and what its rules inspect; antivirus scanning and account permissions perform different jobs.

Guide: Network Antivirus Firewalls: Traffic Inspection, Coverage, and Limits

Reference: NIST: firewall

Compare: Antivirus, Authorization, Segmentation (network security)

A name for the IEEE 1394 serial-interface family, also encountered as i.LINK on some video equipment. It has been used for digital-video transfer and external storage. Identify the equipment’s port, supported transfer mode and computer-driver requirements; matching connectors or a passive cable alone cannot supply a missing interface protocol.

Guide: DV Disk Recorders: Transfer and Check FireStore Footage

Reference: Focus Enhancements: FS-4 HD FireWire interfaces and transfer modes (PDF)

Compare: Interoperability, Container (media file), Timecode

Software and associated data stored in a device to support its operation and hardware functions. A firmware version can affect a receiver’s features, compatibility or behavior. Record the exact device model and installed version when seeking support, and use the manufacturer’s matching update package and procedure.

Guide: GPS Chipsets and GNSS Modules: Selection and Integration

Reference: NIST: firmware

Compare: Software patch, SoC, RTOS

Feline immunodeficiency virus, a virus that attacks a cat's immune system. It is distinct from feline leukemia virus; a veterinarian interprets testing and care needs for the individual animal.

Related coverage: Cat Health Problems: First Visits, FIV/FeLV Tests, and Home Notes

Reference: Cornell: feline immunodeficiency virus

An aircraft recording system that preserves information useful for reconstructing flight events. A flight data recorder stores selected parameters, such as altitude and airspeed; a cockpit voice recorder captures cockpit sounds and communications. These are distinct recording functions. Investigators interpret the recovered records together with other evidence when determining what happened.

Guide: Aircraft Black Boxes: What Flight Recorders Can Reveal

Reference: NTSB: cockpit voice and flight data recorders

Compare: UTC, GNSS

A mechanism that regulates sending so a receiver or intermediate buffer can keep up. Serial connections may use hardware readiness signals, such as RTS/CTS, or software control characters, such as XON/XOFF. Both ends need compatible settings and any required wiring; successful flow control does not by itself confirm that an application processed a message.

Guide: Bluetooth Serial Adapters: Compatibility, Setup, and Testing

Reference: Digi: serial buffering and flow control

Compare: Baud rate, RS-232, Loopback test

An optical property of a lens, usually stated in millimeters, that helps determine angle of view for a given sensor or film format. At the same format, longer focal lengths give a narrower view. An equivalent focal-length label compares angle of view across formats; it does not change the lens’s actual focal length.

Guide: Landscape Photography: Plan the Frame, Light, and Exposure

Reference: Nikon: focal length and angle of view

Compare: Depth of field, Aperture

Falling-object protective structure: a protective structure intended to reduce an equipment operator's exposure to falling objects. Its tested protection level and suitability belong to the exact machine and applicable standard.

Related coverage: Today's Tractors: An Introduction to a Wide Range of Quality Machines

The area shown around the National Hurricane Center's forecast center track to represent track uncertainty. Its circles are sized from historical forecast errors, with two-thirds of those errors inside the circle at each lead time. The cyclone's wind, rain and surge hazards extend beyond its center, so read the separate hazard products alongside the cone.

Guide: Hurricanes: Read the Forecast and Prepare for Each Hazard

Reference: National Hurricane Center: definition of the track forecast cone

Compare: Storm surge

Text that identifies a form control’s purpose, such as Email address beside an input. In HTML, a label element can be associated with a control by matching its for attribute to the control’s unique id, or by containing the control. This relationship helps supply its accessible name; placeholder text is an unreliable substitute for a persistent label.

Guide: Accessibility Evaluation and Repair: From Finding to Retest

Reference: W3C: associating labels with form controls

Compare: Accessible name, HTML, Screen reader

The part of a URL following #, used to identify a location or component within a resource. In a web page it commonly points to an element's ID, such as #term-url; the browser handles it separately from the HTTP request target.

Read the guide: How to Read a URL: Domains, Paths, Queries, and Fragments

Reference: WHATWG URL standard

The number of image frames represented or displayed per second, usually written as fps. Read it alongside the scan type: interlaced field counts describe a different quantity. A label such as 30 fps may also stand for a nearby fractional rate, so inspect the exact timing before editing or converting footage.

Guide: HDV Format: Identify, Capture and Edit Older HD Video

Reference: Adobe: video timing and fields

Compare: Interlaced video, Progressive scan, Shutter speed

A wide-area networking technology that carries frames over virtual circuits. Records for inherited services may describe local circuit identifiers, access rates and committed information rates.

A stored snapshot of selected vehicle operating values associated with a detected fault, such as engine speed, load or temperature. Read it alongside the related diagnostic trouble code to understand the conditions around the event. Save available records before clearing codes, because clearing can remove this context; the captured fields and retention depend on the system.

Guide: Automotive Diagnostics: From a Reported Symptom to a Verified Repair

Reference: OBD Auto Doctor: freeze-frame data and retention

Compare: DTC, OBD

One of the ellipsoidal regions around a radio path used to assess how obstacles affect propagation. For a point-to-point wireless link, clearance of the first Fresnel zone matters as well as the direct sightline. Its size varies with wavelength and position along the path; include terrain, buildings and vegetation when evaluating the link profile.

Guide: Wireless Ethernet Bridges: Plan and Test a Building-to-Building Link

Reference: Cisco Meraki: Fresnel zones and radio path clearance

Compare: Backhaul, Wi-Fi, RSSI

Focal segmental glomerulosclerosis, a pattern of scarring affecting portions of some kidney filtering units, called glomeruli. Different underlying causes can produce this pattern, so the term alone does not establish treatment or prognosis.

Related coverage: FSGS focal segmental glomerulosclerosis kidney disease gene

Reference: National Kidney Foundation: FSGS

The battery system’s estimate of the capacity a battery can hold when fully charged, often reported in milliwatt-hours on a laptop. Compare it with the battery’s design capacity in the same units to help assess wear. It describes estimated capacity; remaining-charge percentage and runtime under a particular workload answer different questions.

Guide: Laptop Batteries and Power Banks: Compatibility, Health, and Runtime

Reference: Microsoft: reported full-charge and design battery capacity

Compare: Milliampere-hour, Kilowatt-hour

G24 Innovations, the company name used in period reports about dye-sensitized solar-cell manufacturing. Those reports document the company's technology and commercial claims at the stated time.

Related coverage: G24i

The ratio of a device's output signal to its input signal under specified conditions. State whether the ratio describes power, voltage or another quantity before comparing values.

Generic Attribute Profile: a Bluetooth framework that organizes application data into services and characteristics and defines ways to discover, read, write and receive updates to that data. It is widely used with Bluetooth LE. Matching the service identifiers, value formats and access requirements matters when connecting an application to a device.

Guide: Bluetooth Development Kits: From Board Selection to a Working BLE Demo

Reference: Bluetooth SIG: Generic Attribute Profile

Compare: Bluetooth Low Energy, Bluetooth pairing, SPP

Gross axle weight rating: the manufacturer's maximum permitted load on a specified axle. Front and rear ratings are separate limits. Compare each axle's measured load in the intended loaded configuration with its rating, while also checking whole-vehicle and tire limits; spare capacity on one axle does not raise the other axle's rating.

Guide: 2008 Nissan Titan: Verify Configuration, Payload and Towing Limits

Reference: Nissan: axle and vehicle weight ratings (2008 Titan manual, PDF)

Compare: GVWR, GCWR, Payload (vehicle)

Gigabits per second: one billion bits per second. It is a rate, while gigabytes describe an amount of data; eight bits make one byte before accounting for transfer overhead.

Gross combined weight rating: the manufacturer's maximum permitted total weight of the loaded tow vehicle and loaded trailer together. Use the rating for the exact vehicle configuration. The combination must also satisfy the separate vehicle, axle, trailer and hitch limits; the combined rating alone does not establish how much trailer can be towed.

Guide: 2008 Nissan Titan: Verify Configuration, Payload and Towing Limits

Reference: Nissan: combined weight rating and towing limits (2008 Titan manual, PDF)

Compare: GVWR, GAWR, Tongue weight

Converting an address or place description into a geographic location, usually coordinates and match information. A returned point may represent a building, a street-range estimate or a broader area. Check the match type and source before using it. Reverse geocoding starts with coordinates and returns a location description.

Guide: Geocoding: Turn Addresses into Coordinates You Can Check · Geoparsing (AI Glossary)

Reference: U.S. Census Bureau: geocoder documentation

Compare: GPS, GNSS

Values that locate a position using latitude and longitude, usually expressed in degrees. Latitude describes north–south position relative to the equator; longitude describes east–west position relative to a prime meridian. Record the coordinate reference system, order, signs and format when exchanging a pair: different tools may expect the two values in different orders.

Guide: Geocoding: Turn Addresses into Coordinates You Can Check

Reference: OGC: geographic coordinates and axis order

Compare: Coordinate reference system, Geocoding, GPS

A gravity-defined level surface used as a reference for heights on Earth, closely associated with global mean sea level. Its irregular shape differs from a smooth reference ellipsoid and from the terrain. A geoid model estimates their separation; survey conversions require a model compatible with the coordinate frame and vertical datum.

Guide: GPS Surveying: Reference Systems, Field Records, and Quality Checks

Reference: NOAA NGS: geoid, ellipsoid and orthometric height relationships

Compare: Ellipsoidal height, Orthometric height, Coordinate reference system

Greenhouse gas: a gas that absorbs and emits infrared radiation and contributes to the greenhouse effect. Carbon dioxide and methane are examples; emissions comparisons require a stated metric and time horizon.

Related coverage: Carbon Capture and Storage: Evaluate the Whole Project

Greenwich Mean Time, a time convention rooted in mean solar time at Greenwich. It is often used for the zero-offset civil time zone; UTC is the international atomic-time-based reference used in modern timekeeping.

Related coverage: UTC definition

Reference: NIST: UTC and other time scales

Global navigation satellite system: the general category of satellite systems that provide positioning, navigation and timing. GPS, Galileo, GLONASS and BeiDou are examples. A multi-constellation receiver can use more than one system, but the supported signals, antenna, operating mode and surroundings still affect its positioning result.

Guide: GPS Chipsets and GNSS Modules: Selection and Integration

Reference: GPS.gov: GNSS systems

Compare: GPS, DGPS

Gallons per minute: a volume flow rate describing how much liquid passes in a minute. Confirm whether the specification uses U.S. liquid gallons or imperial gallons, which have different volumes. For a pressure washer, compare flow together with operating pressure, nozzle and test conditions; maximum flow and maximum pressure may use different configurations.

Guide: Pressure Washers: Match the Machine to the Surface

Reference: NIST: gallon definitions and volume-flow units (PDF) · Generac: pressure and flow rating conditions (PDF)

Compare: PSI

The Global Positioning System, a U.S.-owned satellite system providing positioning, navigation and timing. A receiver uses transmitted satellite information to calculate position and time. GPS is one member of the broader GNSS family; a watch or phone may combine its signals with other constellations when the hardware and selected mode support them.

Guide: GPS Watches: Accuracy, Recording Modes, and Navigation

Reference: GPS.gov: GPS system overview

Compare: GNSS, DGPS, PND

Graphics processing unit: a processor designed for graphics work and many calculations that can run in parallel. Supported software also uses GPUs for rendering, scientific computing and AI. A GPU may be integrated or part of a separate graphics card; the card includes other components such as memory, power circuitry and cooling.

Guide: Choosing a Graphics Card: Workloads, VRAM, Power, and Fit

Reference: IBM: graphics processing units and parallel workloads

Compare: VRAM, PCIe, RAM

The distance on the ground represented by the spacing between neighboring image samples, commonly expressed in centimeters or meters per pixel. For example, a 50-centimeter feature spans about ten samples at 5-centimeter GSD. This describes sampling: image sharpness and independently checked positional accuracy require their own evidence.

Guide: Digital Mapping Camera: From Aerial Images to a Usable Map

Reference: USGS: imagery calibration and ground sample distance

Compare: Spatial resolution (imagery), Map scale

Global System for Mobile Communications, a family of digital cellular standards associated with second-generation mobile service. A phone's supported bands and the continued availability of the network determine usability.

Related coverage: GSM : Global System for Mobile Communications

Global Spectral Model, a name used for global numerical weather-prediction models based on spectral methods. Identify the forecasting organization and model version when interpreting this acronym.

Related coverage: GSM : Global System for Mobile Communications

Gross vehicle weight rating: the manufacturer's maximum permitted total weight of a loaded vehicle, including the vehicle itself, occupants, cargo, fitted equipment and supported trailer tongue load. Compare the actual loaded weight with the rating on the vehicle's certification label. Individual axle limits and towing limits still require their own checks.

Guide: 2008 Nissan Titan: Verify Configuration, Payload and Towing Limits

Reference: Nissan: gross vehicle weight rating and loading limits (2008 Titan manual, PDF)

Compare: Payload (vehicle)

Water containing appreciable dissolved calcium and magnesium, usually reported as hardness equivalent to a concentration of calcium carbonate. Heating it can produce mineral scale in a kettle or other equipment, and it can reduce soap lathering. A hardness result describes these dissolved minerals; drinking-water suitability requires assessment of other constituents and contaminants too.

Guide: Stainless Steel Kettles: Construction, Compatibility, and Care

Reference: USGS: groundwater quality and hardness

Compare: Descaling, Mineral

High-bandwidth Digital Content Protection: a system that authenticates participating devices and encrypts protected content as it travels across supported connections, including HDMI. Playback depends on the required protection support throughout the relevant device chain. Check sources, intermediate equipment and display support when protected video fails to appear.

Guide: HDMI: Choose the Right Connection and Troubleshoot It

Reference: Digital Content Protection: HDCP specifications

Compare: HDMI, DRM, Authentication

High-density lipoprotein, a class of particles that transport cholesterol in blood, including toward the liver. HDL cholesterol is one part of a lipid assessment and is interpreted alongside other measurements and clinical factors.

Related coverage: Olive-Oil Roast Turkey: Plan, Season, Roast and Carve

Reference: NHLBI: blood cholesterol

High-Definition Multimedia Interface: a digital connection standard for audio, video and related signaling. Resolution, refresh rate and other features depend on the capabilities of both devices and the connecting cable.

Read the guide: How to Play DVDs Today: TVs, Computers, Consoles, and Portable Players

High-definition television: television formats with greater picture resolution than standard-definition formats. A useful specification states the image dimensions and scan or frame format, such as 720p or 1080i.

Related coverage: HDTV : High Definition Television

A sealed device that transports heat using a working fluid's evaporation and condensation. Fluid absorbs heat near the source, vapor travels to a cooler region, and condensation releases that heat; a wick commonly returns the liquid. In a computer cooler, the pipe moves heat toward a heat sink, whose surfaces must still transfer it to the surroundings.

Guide: How Heat Sinks Work: Diagnose Cooling with Better Measurements

Reference: Boyd: heat pipes in heat sink assemblies (PDF)

Compare: Heat sink, Thermal interface material

A thermally conductive structure that spreads heat from a component across a larger surface, commonly using a metal base and fins to transfer heat to air. The heat sink itself is passive; a fan may improve airflow through it. Cooling depends on the whole path, including contact with the component and the surrounding air.

Guide: How Heat Sinks Work: Diagnose Cooling with Better Measurements

Reference: Boyd: heat sink basics and fabrication guide (PDF)

Compare: Thermal interface material, Heat pipe, Thermal throttling

Hands-Free Profile: a Bluetooth Classic profile that supports voice connections and call-control functions between a phone and a hands-free device, such as a headset or car system. Available functions and audio capabilities depend on both devices. Check call-audio support and the selected destination separately from whether music playback works.

Guide: Bluetooth Audio: Compatibility, Sound Quality, and Troubleshooting

Reference: Bluetooth SIG: Hands-Free Profile

Compare: A2DP, Audio routing, Bluetooth profile

Human interface device: a category of input and control devices, such as keyboards and pointing devices. USB HID specifications define how supported devices describe and exchange their controls and reports.

Related coverage: MoGo Talk Headset: Charging Design, Variants, and Reuse

Reference: USB-IF: human interface devices

Compare: HID (lighting)

High-intensity discharge: a lamp technology that produces light through an electrical discharge rather than a heated filament. The lamp, ballast and fixture requirements belong to the particular lighting system.

Related coverage: HID lights high intensity discharge lighting

Compare: HID (computer interface)

Hot Import Nights, the name of an automotive-lifestyle event series in period coverage. Event dates and arrangements belong to the particular announcement.

Related coverage: Hot Import Nights

A graph showing how image values are distributed, often from dark tones at the left to light tones at the right, with separate color-channel views sometimes available. Use it alongside the image to assess tonal placement and possible clipping. Its meaning depends on the preview or file being analyzed; there is no universally correct shape.

Guide: Better Phone Photography: Override Auto Exposure on iPhone and Android

Reference: Nikon: reading a camera histogram

Compare: Clipping (imaging), Exposure (photography), Dynamic range (imaging)

Human-machine interface: the controls and displays through which a person interacts with a system. In a vehicle, that includes how information is presented and how a driver operates functions.

Related coverage: Car HMI: Evaluate Controls Before the Test Drive

HyperSonic Sound, a branded directional-audio technology discussed in the linked coverage. Read performance claims with the particular equipment, environment and source date.

Related coverage: Directional Sound: How Ultrasonic Audio Beams Work

HyperText Markup Language: the markup used to describe the structure and meaning of web documents. Elements identify content such as headings, paragraphs, links and form controls; CSS and scripts add presentation and behavior.

Read the guide: What HTML Does: A Small Web Page Explained

Reference: HTML standard

Hypertext Transfer Protocol: the request-and-response protocol used for much of the web. A response carries a status code and may include headers and content; the HTTP version determines how messages are transported.

Read the guide: HTTP and HTTPS: Requests, Responses, and Status Codes

Reference: HTTP semantics (RFC 9110)

HTTP carried over a connection protected by TLS. It protects data in transit and authenticates the server for the requested hostname; judging the accuracy or trustworthiness of the page remains a separate task.

Read the guide: HTTP and HTTPS: Requests, Responses, and Status Codes

Reference: HTTP semantics (RFC 9110)

Hosted web services: software functions supplied over a network by a service provider. An application's behavior can depend on the provider's interfaces, access rules and continued operation.

Related coverage: Samsung bada Geoservices: Maps, Search, Routing, and Platform Lifecycles

The amount of water in dough expressed as a percentage of the flour's weight. For example, 350 g water with 500 g flour gives 70% hydration. Include flour and water contributed by a starter. Recipes may account for other liquids differently, and flour type affects how dough feels at the same stated hydration.

Guide: Pan Pizza: Dough, Pan Size and a Crisp Bottom

Reference: King Arthur Baking: dough hydration and calculation conventions

Indoor air quality: the condition of air inside buildings as it relates to occupants and indoor pollutants. Its assessment considers specific pollutants, ventilation and sources rather than a single universal reading.

Reference: EPA: indoor air quality

Integrated Digital Enhanced Network, Motorola's cellular technology combining telephone and dispatch-style push-to-talk services. It is a historical network family; operation of surviving equipment requires a compatible active service.

Related coverage: Motorola iDEN: Push-to-Talk, Dispatch Networks, and Their Legacy

Rock formed as molten material cools and solidifies. Cooling history influences its texture: slow cooling beneath the surface often allows larger crystals, while rapid cooling can produce finer textures or glass.

Read the guide: Rocks and Minerals: A Guide to Observing and Understanding Them

Reference: National Park Service: rocks

Integrated Motor Assist, Honda's name for a hybrid system in which an electric motor assists the engine. The exact vehicle generation determines its mechanical arrangement and operating behavior.

Related coverage: Honda Insight concept

IP Multimedia Subsystem: a telecommunications architecture for delivering multimedia services over IP networks. It coordinates functions such as registration and session control rather than naming a particular handset.

Related coverage: Gigabit Ethernet Test Equipment

International-Matex Tank Terminals, a company name encountered in bulk-liquid storage and terminal coverage. Here the acronym identifies an organization rather than a heat-transfer-fluid specification.

Related coverage: Heat transfer fluid

Producing heat in a suitable conductive object through a changing magnetic field. In an induction cooktop, the field induces electrical currents in compatible cookware, generating heat in the vessel. Check the vessel’s induction rating and the cooktop’s base-size requirements; a stainless-steel label alone leaves the magnetic base construction unspecified.

Guide: Stainless Steel Kettles: Construction, Compatibility, and Care

Reference: U.S. Department of Energy: induction cooking

Compare: Watt, Kilowatt-hour

Protecting information and systems against unauthorized access, disclosure, alteration or disruption. Confidentiality, integrity and availability describe complementary goals of that protection.

Reference: NIST: information security

An organized combination of people, processes, data and technology that collects, handles or communicates information. Reviewing a system includes how people use it as well as its hardware and software.

Printing that deposits fine droplets of liquid ink through nozzles onto a medium such as paper. Photo results depend on the printer, ink, paper, color settings and maintenance. Compare supported media and the complete printing workflow alongside resolution figures; a printer’s dot specification and an image’s pixels per inch describe different things.

Guide: Photo Printers: Choose a Method and Plan the Real Cost

Reference: Canon: how inkjet printing works

Compare: Dye-sublimation printing, Borderless printing, PPI

Video organized into two alternating fields per frame, one containing odd-numbered image lines and the other even-numbered lines. In interlaced capture, the fields can represent different moments. Field order matters when decoding or converting motion; combining fields incorrectly can produce comb-like edges or uneven movement.

Guide: HDV Format: Identify, Capture and Edit Older HD Video

Reference: Adobe: interlaced video and field order

Compare: Progressive scan, Frame rate, Transcoding

Radio programming delivered through an internet connection as an audio stream. Playback depends on access to the station's stream and on the receiver or app supporting the service and format.

Read the guide: Internet Radios: Choose a Receiver, Find Stations, and Set It Up

The ability of systems to exchange information and use it meaningfully. Matching a file format is only part of the task; interpretation, versions and agreed conventions also matter.

Estimating values between known data points using a stated mathematical method. Linear interpolation follows a straight line between neighboring points; other methods make different assumptions. An interpolated value is an estimate to label separately from an original observation. Estimating beyond the data's covered range is extrapolation, with different risks and assumptions.

Guide: Data Loggers: Plan a Measurement You Can Trust

Reference: SciPy: linear interpolation, splines and extrapolation

Compare: Sample rate, Aliasing (sampling), Computational reproducibility

Input/output operations per second: the rate at which storage read or write operations are completed or counted. Compare figures with the request size, read/write mix, access pattern, concurrency and measurement point stated. IOPS describes an operation rate; throughput describes data volume per second, and latency describes the time an operation takes.

Guide: Disk Storage Systems: Match Architecture to Workload

Reference: AWS: I/O size, IOPS, throughput and latency

Compare: Throughput, Latency

Internet Protocol: the network-layer protocol family used to address and carry packets between networks. IPv4 and IPv6 provide different address formats; delivery behavior also depends on other protocols and the path.

A classification under the IEC 60529 IP Code describing protection provided by an equipment enclosure against access to hazardous parts and the entry of solid objects or water. Read the exact rating with its test conditions and the product’s instructions, including required covers. Impact resistance and charging precautions need their own specifications.

Guide: Rugged Bluetooth Speakers: Water Protection, Battery Life, and Outdoor Use

Reference: IEC: enclosure protection and the IP Code

Compare: IP

A camera setting that relates the exposure to the resulting image brightness. In a digital camera, raising ISO can make the output brighter for the same captured light; aperture and exposure time control how much light is collected. Higher ISO often accompanies shorter exposures or dimmer scenes, where noise and usable detail deserve attention.

Guide: Better Phone Photography: Override Auto Exposure on iPhone and Android

Reference: Nikon: ISO sensitivity

Compare: Aperture, Shutter speed, Exposure compensation

A form of an element with the same number of protons but a different number of neutrons. Some isotopes are stable and others decay radioactively; isotope measurements can inform geological history when used with a suitable method.

Read the guide: What Rocks Reveal About Earth's Interior

Variation in packet delay over time. Real-time voice and video systems may buffer arriving data to absorb some variation, trading additional delay for steadier playback.

A chronological record of operations or changes. In a database or storage system, a journal can support recovery, but its contents and guarantees depend on the implementation.

An input control whose movement supplies direction or position information to a system. Joysticks are used in games, simulation and equipment control, with capabilities determined by the device and software.

The core of an operating system that manages resources and provides essential services to software. Its responsibilities commonly include memory, scheduling and interaction with device drivers.

An input device with keys used to enter characters and commands. Its physical layout, key mapping and connection method are separate compatibility considerations.

The state that identifies which interface element currently receives keyboard input. A visible focus indicator helps users locate that element as they move through links, buttons and fields. Test both where focus moves and whether it remains visible; a screen reader’s reading position can be separate from keyboard focus.

Guide: Website Accessibility Check: A Practical First Audit

Reference: W3C: Focus Visible

Compare: Keyboard, Screen reader, Reading order

An energy unit equal to using one kilowatt continuously for one hour, or 3.6 million joules. For example, 2 kW sustained for half an hour uses 1 kWh. At a hypothetical energy price of $0.20 per kWh, that energy costs $0.20 before other charges. Distinguish energy purchased at the meter from energy stored in a battery.

Guide: Green Cars: Compare the Whole Transportation Choice

Reference: NIST: energy-unit conversions

Compare: Watt

Local area network: a network connecting devices within a limited site, such as a home, office or campus. Ethernet and Wi-Fi can provide different kinds of connections within the same LAN.

The cool phase of ENSO, involving below-average sea-surface temperatures in the central and eastern tropical Pacific and associated changes in atmospheric circulation. Equatorial trade winds typically strengthen. La Niña can shift seasonal weather probabilities, but its effects vary by region, season and event; the phase name does not guarantee a particular day's weather.

Guide: La Niña Explained: ENSO, RONI and Seasonal Outlooks

Reference: NOAA National Weather Service: La Niña

Compare: ENSO, El Niño

Large Area Telescope, the gamma-ray instrument aboard the Fermi space telescope. In astronomy reporting, identify the instrument and observing conditions when interpreting a measurement.

Related coverage: Microquasar Jets: Following Cygnus X-3 Across Wavelengths

The delay for a specified operation or communication. Network measurements may describe one-way delay or round-trip time, so keep that distinction and the units with the result. Low latency helps interactions respond promptly.

Read the guide: Technology Terms That Help You Read Product Specifications

Compare: Bandwidth (network capacity), Throughput

Lunar Crater Observation and Sensing Satellite, NASA's lunar-impact mission used to investigate material near the Moon's south pole. Its results are evidence from a particular impact site and observing campaign.

Related coverage: Water on the Moon: Ice, Molecules, Measurements and Resources

Low-density lipoprotein, a class of particles that carry cholesterol in blood. Elevated LDL cholesterol can contribute to plaque buildup in arteries; interpretation and treatment decisions use the person's broader clinical assessment.

Related coverage: Olive-Oil Roast Turkey: Plan, Season, Roast and Carve

Reference: NHLBI: blood cholesterol

Lane-departure warning: a driver-assistance function that warns when a vehicle may leave its lane under supported conditions. A warning function and an active steering intervention are different capabilities.

Related coverage: Lane Departure Warning: Understand the Alerts and Limits

The principle of granting a person, device or process only the access needed for its assigned work. Apply it to allowed actions and resources, such as letting a guest network reach the internet while restricting access to internal administration. Review permissions when responsibilities change; successful authentication alone does not determine the appropriate access.

Guide: Secure Workplace Wi-Fi: Access Policies and Verification

Reference: NIST: least privilege

Compare: Authorization, Segmentation (network security), App permission

The expansion that makes a batter or dough rise as gas forms or expands within it. Depending on the recipe, yeast, chemical leaveners, incorporated air or steam provide the lift. Baking soda and baking powder have different compositions and reaction requirements; they are not interchangeable spoon for spoon. The mixture must hold the expanding gas as its structure sets.

Guide: Buttermilk and Fruit Pancakes: A Measured Method

Reference: King Arthur Baking: steam leavening and batter structure · King Arthur Baking: yeast, baking powder and baking soda

Compare: Creaming (baking), Hydration (baking)

Linksys EasyLink Advisor, a name used for network setup and management software in historical Linksys coverage. Supported devices and operating systems depend on the specific software release.

Related coverage: Cisco Linksys WRT160NL Media Router

A record or plot of an astronomical source's measured brightness over time. The quantity may be flux, magnitude or a detector count rate, with a stated wavelength or energy range. Check time bins, uncertainties and upper limits when interpreting a flare or dip; averaging over longer bins can smooth short-lived changes.

Guide: Fermi Gamma-ray Telescope: How to Read Its Sky and Alerts

Reference: NASA Fermi: light-curve measurements, time bins and interpretation

Compare: Transit (astronomy), Spectrum (light), LAT

The distance light travels through a vacuum in one year, approximately 9.46 trillion kilometers. It is a unit of distance used for stars and galaxies. When reading a cosmological distance in light-years, check which distance definition is intended: the separation today can differ from the distance obtained by multiplying light's travel time by its speed.

Guide: The Most Distant Galaxies: Redshift, Lookback Time and Confirmation

Reference: NASA Space Place: light-years as a distance unit

Compare: Lookback time, Redshift

Local Interconnect Network: a serial communication bus used for relatively simple connections among vehicle components. It provides a different cost and capability tradeoff from higher-speed automotive networks.

Related coverage: Automotive LIN Electronics: Nodes and Power States

Reference: Microchip: Local Interconnect Network

A module providing network interfaces and related functions within equipment such as a modular router. Port types, supported modules and software compatibility determine its role in a particular chassis.

An analog audio output intended to feed a line-level input on another device. Check level, connector and whether volume is fixed or adjustable; a passive loudspeaker requires a suitable amplifier.

Read the guide: Internet Radios: Choose a Receiver, Find Stations, and Set It Up

Combining multiple connections into a logical transport using cooperating equipment or endpoints. Some internet bonding systems distribute packets from one session across several links and reassemble them at the other end. Useful capacity depends on the implementation, endpoint, overhead and link behavior; verify single-transfer performance separately from total traffic across many sessions.

Guide: Wireless Bandwidth Aggregation: Bonding, Balancing and Failover

Reference: Peplink: packet-level bandwidth bonding

Compare: Load balancing, Failover, Latency

The timing alignment between sound and the visible action it accompanies, such as speech matching a person’s mouth movements. Different audio and video processing paths can create an offset. An audio-delay setting can correct some mismatches; the appropriate adjustment depends on which signal arrives first and the available controls.

Guide: HDMI: Choose the Right Connection and Troubleshoot It

Reference: Yamaha: lip-sync adjustment

Compare: Latency, AV receiver, HDMI

Distributing work or traffic among available resources. For multiple internet connections, a router often assigns sessions to different links according to a policy, improving capacity across simultaneous users or transfers. The speed of one session can remain limited to its assigned path; check how the implementation handles new sessions, failures and applications needing a stable address.

Guide: Wireless Bandwidth Aggregation: Bonding, Balancing and Failover

Reference: Peplink: internet load balancing and traffic policies

Compare: Failover, Link bonding, Throughput

The elapsed time between light's emission and its arrival at the observer. It describes how far into the past an astronomical observation reaches. For distant galaxies, deriving lookback time from redshift requires a cosmological model. Keep this travel time separate from the universe's age at emission and from the galaxy's present-day distance.

Guide: The Most Distant Galaxies: Redshift, Lookback Time and Confirmation

Reference: NASA Webb: why distant observations reveal earlier epochs

Compare: Light-year, Redshift

A test that returns transmitted data to its sender so the returned data can be compared with what was sent. A serial loopback can help isolate an interface or connection fault. Use the documented test arrangement for the equipment and record which part of the path it covers; a passing result leaves the remaining application path to check.

Guide: Bluetooth Serial Adapters: Compatibility, Setup, and Testing

Reference: Digi: testing a serial connection with a loopback plug

Compare: RS-232, Flow control, Regression testing

Compression that allows the data supplied to the compression stage to be reconstructed exactly. It reduces storage needs while preserving that input. A lossless copy of a previously lossy recording retains the data it receives; detail discarded earlier stays missing. For video workflows, check that surrounding conversions also preserve the required data.

Guide: Lossless Video Codecs: Masters, Editing and Viewing Copies

Reference: Library of Congress: lossless FFV1 video

Compare: Lossy compression, Codec, Checksum

Compression that discards some information to reduce the amount of data. Audio or video quality depends on the source, codec and encoding settings; artifacts can become visible or audible as information is lost. Repeated decoding and lossy re-encoding can add further loss, so keep a suitable master for future edits.

Guide: Lossless Video Codecs: Masters, Editing and Viewing Copies

Reference: MDN: video codecs and compression

Compare: Lossless compression, Codec, Container (media file)

Long Term Evolution, a family of mobile-network radio technologies associated with 4G service. Frequency bands, device support and network configuration determine the capabilities available on a connection.

Related coverage: Verizon LTE: Device Compatibility, Activation and Coverage Checks

Linear Tape File System: a format and file-system approach that presents compatible tape contents as files and directories, using separate index and data partitions. Reading an LTFS tape requires compatible media, a drive and supported software. An application-specific backup tape may instead need that application's restore tools and catalog, so record the format alongside the media generation.

Guide: LTO-8 Tape Archives: Compatibility, LTFS, and Restore Planning

Reference: LTO Program: Linear Tape File System · LTO Program: media and drive compatibility

Compare: File system, Backup, Restore (data)

A specification for compact modules and their connectors, used for SSDs and other devices. An M.2 storage module may use SATA or PCIe/NVMe, depending on the device and host. Length, connector keying, interface support and clearance all matter; a similar-looking module or enclosure does not establish compatibility.

Guide: Toshiba XG5-P Client NVMe SSD: Compatibility and Upgrade Checks

Reference: Dell: M.2 sizes, keys and interfaces

Compare: NVMe, SSD

Machine-to-machine communication: exchanging information between devices, often for monitoring or control. It can use cellular or other networks and does not require a person to initiate every exchange.

Related coverage: Machine-to-machine cellular communication smart card

Software or code designed to perform harmful or unauthorized actions. Viruses, ransomware and spyware describe different behaviors within this broad category; identifying the behavior helps guide containment and recovery.

Read the guide: Anti Virus and Malware: Protection, Recovery, and Outbreak Lessons

Reference: NIST: malware terminology

Compare: Computer virus, Ransomware, Quarantine (security software)

A mathematical way to represent Earth’s curved surface on a flat map. Projections preserve selected properties while introducing distortion in others, such as area, shape, direction or distance. Choose one suited to the region and purpose. A projected coordinate reference system also supplies the reference framework, axes, units and projection parameters.

Guide: Wall Maps: Choose the Scale and Check the Print

Reference: USGS: map projections and their uses

Compare: Coordinate reference system, Map scale

The relationship between a distance on a map and the corresponding ground distance. At 1:25,000, one centimeter represents 250 meters where that scale applies. Resizing a print changes its numerical scale; a scale bar resized uniformly with the map remains useful. Projection distortion can make scale vary across a map.

Guide: Wall Maps: Choose the Scale and Check the Print

Reference: USGS: interpreting map scale

Compare: Map projection, Vertical exaggeration, Ground sample distance

An analytical method that forms gas-phase ions and measures their signals according to m/z, supporting investigation of composition, structure or amount. A mass spectrum relates ion signals to mass-to-charge values. Interpreting peaks requires the ionization method, reference evidence and suitable checks; optical spectroscopy instead examines how matter interacts with light.

Guide: Mass Spectrometry: Read the Signal and Understand the Evidence

Reference: IUPAC: mass spectrometry terminology, MSACL-hosted PDF

Compare: Mass-to-charge ratio, Chromatography, Spectrum (light)

Common label for m/z in mass spectrometry: an ion's mass in unified atomic mass units divided by its charge-number magnitude. IUPAC recommends m/z for this dimensionless quantity. A hypothetical 600-u ion with two positive charges has m/z 300. Relating that value to a neutral molecule's mass also requires the charge state and the ion's composition.

Guide: Mass Spectrometry: Read the Signal and Understand the Evidence

Reference: IUPAC: m/z definition and notation, MSACL-hosted PDF

Compare: Mass spectrometry, Retention time (chromatography)

A megabit is 1,000,000 bits, equivalent to 125,000 bytes. Mb describes an amount of data; Mbps describes a rate. The lowercase b distinguishes bits from bytes.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: NIST: bits, bytes and prefixes

Compare: MB (megabyte), Mbps, MB/s

A megabyte is 1,000,000 bytes in decimal notation. MiB means 1,048,576 bytes. Uppercase B matters: Mb means megabit, and MB/s means megabytes per second rather than an amount of stored data.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: NIST: bits, bytes and prefixes

Compare: Mb (megabit), Mbps, MB/s

Megabits per second: one million bits per second. Divide by eight for the equivalent decimal megabytes per second before transfer overhead: 80 Mbps corresponds to 10 MB/s at that arithmetic limit.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: NIST: bits, bytes and prefixes

Compare: MB (megabyte), Mb (megabit), MB/s

Megabytes per second: a data-transfer rate measured in millions of bytes per second. With eight bits per byte, 10 MB/s equals 80 Mbps before protocol overhead. The uppercase B distinguishes bytes from bits.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: NIST: bits, bytes and prefixes

Compare: MB (megabyte), Mb (megabit), Mbps

Mobile digital television: broadcast television intended for compatible mobile receivers. The transmission standard and local broadcast service determine what a device can receive.

Related coverage: GPS and Mobile Digital TV: Why Navigation Devices Added Broadcast Receivers

The smallest change in the measured quantity that produces a discernible change in an instrument's indication. It can depend on noise, operating conditions and the value being measured. Extra displayed decimal places describe a readout's detail; determining how closely the result agrees with a reference requires separate evidence about measurement performance.

Guide: Data Loggers: Plan a Measurement You Can Trust

Reference: JCGM VIM: resolution

Compare: Sensor response time, Repeatability (measurement), Signal-to-noise ratio

One million image pixels. A pixel count describes image dimensions, while lens performance, noise, processing and viewing size also influence useful detail. Multiplying pixel width by pixel height gives the total pixel count.

Read the guide: CMOS Image Sensors: Size, Pixels, Noise and Shutter Readout

Reference: Canon: image sensors

Information that describes data or a digital object, such as its creator, capture date, format, keywords or identifiers. For a photograph, metadata can preserve context alongside the image itself. It may be embedded in the file or stored separately, so check what survives when files are exported, copied or shared.

Guide: Digital Photo Albums: Select, Sequence, Caption and Share · Metadata Enrichment (AI Glossary)

Reference: NIST: metadata

Compare: Sidecar file, Embedded profile, RAW image file

Rock changed by heat, pressure or chemically active fluids while remaining largely solid. Its minerals and textures reflect the conditions of that change and the composition of the starting rock.

Read the guide: Rocks and Minerals: A Guide to Observing and Understanding Them

Reference: National Park Service: rocks

A unit of electric charge, abbreviated mAh, equal to one-thousandth of an ampere-hour. Battery energy also depends on voltage: a hypothetical 10,000 mAh rating at 3.7 V corresponds to 37 Wh before conversion losses. Use the voltage associated with the capacity rating when comparing batteries; USB output voltage may describe a different measurement point.

Guide: Laptop Batteries and Power Banks: Compatibility, Health, and Runtime

Reference: FAA: converting battery ampere-hours and voltage to watt-hours

Compare: Kilowatt-hour, Full-charge capacity

Multipurpose Internet Mail Extensions: conventions for describing and packaging different kinds of content. MIME media types such as text/html and image/jpeg also tell web software what kind of representation it is handling.

Read the guide: MIME Types: How Email and the Web Identify Content

Reference: MIME media types (RFC 2046)

A naturally occurring solid with a characteristic chemical composition and ordered internal structure. Rocks commonly contain mixtures of minerals; observing color alone is usually insufficient for identification.

Read the guide: Rocks and Minerals: A Guide to Observing and Understanding Them

Reference: National Park Service: minerals

A cut angled across a board's face instead of square across its length. On a miter saw, turning the table sets this angle; tilting the blade sets a bevel through the board's thickness. A compound cut combines both adjustments. A 45-degree miter is a common example, not the definition of every miter cut.

Guide: Miter Saws: Choose Capacity and Check the Cut

Reference: DeWalt: miter, bevel and compound cuts (PDF)

Compare: Tear-out, Clamp force

Multiple Launch Rocket System, a term used for a military launcher/system family. Distinguish a launcher from guided rocket munitions such as GMLRS when reading program descriptions.

Related coverage: GMLRS Explained: Rocket Families, Launchers, and Program Milestones

Marvell Mobile Hotspot, the product name abbreviated MMH in period mobile-connectivity reporting. It refers to that vendor's implementation rather than every device that shares a mobile connection.

Related coverage: Mobile hotspot

Minerals Management Service, the former U.S. agency responsible for offshore energy and mineral-resource functions. Use the agency name with the historical date because those responsibilities were reorganized.

Related coverage: U.S. Oil Production: Read Trends, Revisions and Forecasts

Multimedia Messaging Service: a mobile messaging service that can carry content such as pictures with messages. Device, carrier and service support affect delivery and supported media.

Related coverage: MMS : Multimedia Messaging Services

Mobile network operator: an organization operating a mobile communications network. Its network infrastructure and service arrangements distinguish its role from other companies selling mobile services.

Related coverage: Service delivery card

Administration of enrolled phones, tablets and other endpoints through a management service, often abbreviated MDM. Depending on the platform and enrollment type, it can apply settings, deploy apps, assess policy compliance and issue remote lock or erase commands. Establish ownership and the management boundary so users and administrators understand which data and controls are covered.

Guide: Mobile-Device Security: Enrollment, Loss Response, and Retirement

Reference: Apple: device management capabilities and enrollment

Compare: App permission, Least privilege, Data sanitization

Multiprotocol Label Switching: forwarding network traffic using labels assigned to a path or forwarding class. Labels help organize traffic through an MPLS network; service behavior also depends on its configuration.

Related coverage: MPLS

Magnetic resonance imaging: forming detailed internal images using strong magnetic fields, radiofrequency signals and measured responses from the body. Scan suitability and precautions are assessed for the individual patient.

Related coverage: MRI Machines: What They Look Like and What to Expect

Reference: NIBIB: magnetic resonance imaging

MultiTransport Networking Service, a service name in historical telecommunications coverage. Its supported transport types and commercial terms belong to the named service and announcement date.

Related coverage: MTNS: MultiTransport Networking Service

Megatransfers per second: millions of data transfers per second. In a DDR memory specification, 3,200 MT/s corresponds to a 1,600 MHz clock because there are two transfers per clock cycle. The transfer-rate figure describes signaling; calculating byte bandwidth also requires the data-path width, while application performance depends on the wider system.

Guide: RAM Upgrades: Capacity, Compatibility, and Stable Settings

Reference: Kingston: MT/s, clock frequency and memory bandwidth (PDF)

Compare: DDR, RAM, Latency

Maximum transmission unit: the largest packet or protocol data unit a link or interface can carry at the layer being discussed without fragmentation. A path may impose a smaller limit than the local interface, affecting connectivity and performance.

Read the guide: PPP and PPPoE: Sessions, Authentication, and Troubleshooting

Reference: PPP over Ethernet (RFC 2516)

A type of rewritable, nonvolatile semiconductor memory that retains stored data without continuous power, widely used inside storage devices. In 3D NAND, memory cells are arranged in stacked layers. Layer count describes that structure; bits per cell describes how much information each cell holds. A finished device also needs control and interface functions.

Guide: 64-Layer 3D NAND Explained: Flash Memory and UFS

Reference: KIOXIA: three-dimensional flash memory · KIOXIA: NAND, nonvolatile memory and bits per cell

Compare: UFS, SSD, PCM (memory)

Network-attached storage: a system that provides shared file storage over a network. A NAS can hold working files, receive backups, or do both, depending on its configuration. Plan user access, usable capacity and recovery separately; files whose only copy lives on the NAS still need an independently recoverable backup.

Guide: Network Attached Storage: Capacity, Sharing, and Recovery

Reference: IBM: network-attached storage

Compare: RAID, Backup, File system

Network Address Translation: rewriting IP address information as traffic passes between networks. A common form also translates transport ports so several devices can share one external IPv4 address. Translation determines how addresses are mapped; firewall rules separately determine which traffic is permitted. Trace both functions when diagnosing a connection.

Guide: Wireless Firewalls: Trace Rules, NAT and Connection Failures

Reference: RFC 3022: traditional NAT and port translation

Compare: IP, Router, Firewall

Computational methods for working with human language in text or speech. Tasks include recognizing structure, extracting information and generating language; useful performance depends on the task and evaluation.

Naval Air Systems Command, the U.S. Navy organization associated with naval aviation systems. The acronym identifies the organization in program and research reporting.

Related coverage: Ferrium C61 C64 alloys

Naval Sea Systems Command, the U.S. Navy organization associated with ships and related systems. Keep the command, contractor and specific program distinct when following a development project.

Related coverage: Composite Ballistic Screens: The DDG-1000 Development Case

The name of a major randomized lung-cancer screening trial conducted in the Netherlands and Belgium using CT screening. Trial findings apply to the studied population and protocol; individual screening decisions use current clinical guidance.

Related coverage: Lung cancer screening

Reference: NEJM: the NELSON randomized trial

Network equipment manufacturer: a company that makes equipment used in communications networks. The term describes a supplier role rather than a particular protocol or performance level.

Related coverage: Gigabit Ethernet Test Equipment

A boundary where users, devices or other networks connect to the network being described. Its location depends on the scope of the diagram or service under discussion.

Near-field communication: short-range wireless communication used when compatible devices or tags are brought close together. Payments, identification and tag reading use different application and security arrangements.

Related coverage: NFC Explained: Tags, Payments, Pairing, and Failed Taps

Network service provider: an organization supplying network connectivity or related services. A service description should identify its coverage, handoff and responsibilities.

Related coverage: Gigabit Ethernet Test Equipment

NVM Express: a protocol and specification family for communicating with nonvolatile storage. In a typical client SSD, NVMe commands travel over PCIe; M.2 describes a physical module format. Check the host’s supported protocol and interface as well as the drive’s dimensions. NVMe also has transport specifications for networked storage.

Guide: Toshiba XG5-P Client NVMe SSD: Compatibility and Upgrade Checks

Reference: NVM Express: specifications and transports

Compare: SSD, M.2

On-board diagnostics: a vehicle's built-in monitoring and reporting capabilities. Standardized OBD-II diagnostics monitor emission-related systems and provide information that a compatible scan tool can retrieve, including trouble codes. Access to additional modules, live data and service functions depends on the exact vehicle, tool and software; check the specific task's coverage.

Guide: Car Scan Tools: Choose the Coverage You Actually Need

Reference: California Air Resources Board: OBD-II systems

Compare: DTC, Freeze-frame data (vehicle)

Optical character recognition: converting pictures of written or printed text into machine-readable characters. Layout, image quality and the writing system affect accuracy, so important extracted text needs checking.

Related coverage: Scanning pen

A thin strand of transparent material that guides light carrying information. Fiber type, optical wavelength, transceivers and the link's losses determine the connection it can support.

Off-premises extension: a telephone extension located away from the premises containing its main switching system. Its connection and service arrangement determine how calls reach it.

Related coverage: PBX definition

Height relative to the geoid, measured along the direction of gravity and commonly written H. It provides the basis for many surveyed elevations. The usual conversion is H = h − N, using compatible ellipsoidal height h and geoid height N. Record the vertical datum and model because height references can differ between datasets.

Guide: GPS Surveying: Reference Systems, Field Records, and Quality Checks

Reference: NOAA NGS: orthometric heights, datums and geoid corrections

Compare: Geoid, Ellipsoidal height, Relative sea level

The Open Systems Interconnection reference model, which organizes communications functions into seven layers. It is useful for describing responsibilities and troubleshooting, while real protocol stacks may cross or combine its conceptual boundaries.

Read the guide: OSI Layers in Practice: Follow a Connection, Find a Fault

Reference: ITU: OSI reference model

A unit of data carried through a packet network, with control information and a payload. The protocol determines its fields; not every packet contains all the information needed to order a complete application message.

Sharing network links by transmitting data in separate packets. Different flows can use the same link; delivery, ordering and recovery from loss depend on the protocols used.

A supported power-bank operating mode that accepts input power while supplying a connected device. Available output and whether the battery gains charge depend on the model, input supply and load. Check the manufacturer’s stated arrangement and limits; this feature alone does not establish uninterrupted operation when input power is removed.

Guide: Laptop Batteries and Power Banks: Compatibility, Health, and Runtime

Reference: Anker: model-specific pass-through charging conditions

Compare: USB Power Delivery, Watt

Software that stores account credentials and helps create and fill unique passwords. It can reduce the need to remember a different complex password for every account. Features such as synchronization, sharing and passkey storage vary by product; understand how to unlock the manager and recover access before relying on it.

Guide: Antivirus Protection: What You Need and How to Check It

Reference: Apple: generating, storing and filling passwords

Compare: Authentication

A transmission-line balancing arrangement used to connect an unbalanced coaxial feed to a balanced antenna. This is a specialized antenna term; construction dimensions depend on the design and operating frequency.

Reference: Eindhoven University: antenna research (PDF)

The load a vehicle carries, including occupants, cargo and added equipment; a payload capacity states the permitted allowance for that load. Trailer tongue load supported by the vehicle also consumes the allowance. Use the actual vehicle's loading label and configuration, then check whole-vehicle, axle and towing limits separately.

Guide: 2008 Nissan Titan: Verify Configuration, Payload and Towing Limits

Reference: Nissan: vehicle loading and payload definitions (2008 Titan manual, PDF)

Compare: GVWR

Private branch exchange: a telephone switching system serving an organization and connecting its internal extensions with outside telephone services. Implementations may use traditional telephone circuits, IP networks or a hosted service.

Read the guide: Telephone Guides: Find Help by Task or Topic

Reference: NIST: private branch exchange

PCI Express: a serial interconnect used by devices such as graphics cards and NVMe SSDs. A link’s generation and active lane count determine its connection capacity; x4 describes four lanes. The host and device must support the connection, while actual transfer rates also depend on the device, workload and other system limits.

Guide: Toshiba XG5-P Client NVMe SSD: Compatibility and Upgrade Checks

Reference: PCI-SIG: PCI Express FAQ

Compare: NVMe, M.2, Throughput

Pulse-code modulation: representing a sampled signal with a sequence of numerical sample values. Sample rate and bit depth describe different aspects of a PCM audio representation.

Related coverage: Phase-Change Memory: How It Stores Data and How to Evaluate Its Tradeoffs

Compare: PCM (memory), PLC (audio)

Phase-change memory: storing information through distinguishable physical states of a material. The memory-device implementation determines its capacity, endurance and electrical interface.

Related coverage: Phase-Change Memory: How It Stores Data and How to Evaluate Its Tradeoffs

Compare: PCM (audio), PLC (audio)

Professional Developers Conference, Microsoft's historical developer-event name. References to its announcements should retain the conference date and the software generation being discussed.

Related coverage: Veriplace: Carrier Location Services and Their Dependencies

A unit for the arithmetic difference between two percentages. An increase from 40% to 45% is five percentage points; relative to the starting value, it is a 12.5% increase because 5 ÷ 40 × 100 = 12.5. State which comparison you mean when describing rates, shares or study results.

Guide: Research Design Tools: Turn a Question into a Testable Experiment

Reference: Eurostat: percentage points (PDF)

Representing a byte in a URL as % followed by two hexadecimal digits. For example, %20 represents a space; the correct treatment depends on which URL component is being encoded.

Read the guide: How to Read a URL: Domains, Paths, Queries, and Fragments

Reference: WHATWG URL standard

Characterizing observable traits or identifying clinical groups from information such as records, measurements or tests. The definition and validation of a phenotype determine what a study's groups actually represent.

Reference: Research: phenotyping clinical records

A deceptive communication that impersonates a trusted source to induce an action such as revealing credentials, sending money or opening a harmful link or attachment. Phishing can arrive through email, text or other channels. A familiar sender name or a message passing a filter is insufficient evidence that its request is legitimate.

Guide: SpamSquelcher and the Challenge of Accurate Spam Filtering

Reference: NIST: phishing

Compare: Email spoofing, Malware, Authentication

A coloring material dispersed in a medium such as paint. Its chemical and physical properties affect appearance and aging; a painted color can change through interactions involving pigment, binder, light and environment.

Read the guide: How to Look at Seurat’s La Grande Jatte

Reference: Art Institute: Seurat's materials

Compare: Pointillism, Composition (art)

A preliminary hole that guides a later drilling or fastening operation. For a wood screw, it prepares the material that the threads will engage and can reduce splitting or excessive driving resistance. Select the size and depth from the fastener and material guidance; a clearance hole instead lets the fastener pass through a part.

Guide: Drill Bits: Match the Material, Hole and Drill

Reference: Bosch: pilot and clearance holes for screw fastening (PDF)

Compare: Clearance hole

A group of feldspar minerals forming a compositional series between sodium-rich and calcium-rich end members. It is common in many igneous rocks, including tonalite; composition and mineral proportions help distinguish rock types.

Read the guide: Tonalite: Composition, Formation, and Comparison with Granite

Reference: National Park Service: minerals

Compare: Tonalite, Quartz

A small solid body formed during planetary assembly that can contribute material to larger bodies through growth and collisions. Surviving remnants help researchers investigate early planetary systems. Describing an object as a planetesimal concerns its origin and role; later heating, impacts or capture can alter it, as models of Saturn's moon Phoebe illustrate.

Guide: Phoebe: What Cassini Revealed About a Captured Moon

Reference: NASA: Phoebe as an evolved planetary building block

Compare: Digital elevation model, Spectrum (light)

Packet-loss concealment: techniques that estimate or substitute audio when expected packets are missing. Concealment can reduce the audible effect of loss, but cannot reconstruct every missing sound exactly.

Related coverage: MoGo Talk Headset: Charging Design, Variants, and Reuse

Compare: PCM (memory), PCM (audio)

Polarized light microscopy: examining a specimen using polarized light to reveal optical properties and structure. Interpretation depends on the specimen preparation, instrument arrangement and material.

Reference: Nikon: polarized light microscopy

Product lifecycle management: organizing product information and changes across design, manufacturing, service and retirement. Traceable versions and responsibilities help people work from the same product record.

Related coverage: 3D PLM: Keep Structural Analysis Linked to the Design Revision

Personal navigation device: a dedicated portable device for route guidance and position display. Positioning signals, map data and traffic information are separate inputs with separate update requirements.

Related coverage: GPS and Mobile Digital TV: Why Navigation Devices Added Broadcast Receivers

Power over Ethernet: supplying electrical power to compatible equipment through Ethernet cabling. The power standard, available budget and powered device's needs must agree.

Related coverage: Network cameras for school corridors and entrances

A painting technique using small, distinct touches or dots of color to build an image. It is associated with Neo-Impressionist artists including Georges Seurat; viewing distance affects how the marks and colors are perceived.

Read the guide: How to Look at Seurat’s La Grande Jatte

Reference: Art Institute of Chicago: La Grande Jatte

Compare: Composition (art), Pigment

Point of presence: a location where a provider makes network connectivity or related services available. The equipment and interconnections at that location determine its role.

A physical connection point for a network interface, such as an Ethernet socket or optical-module slot. Its connector, signaling standard and supported equipment must be considered together.

Pixels per inch: the number of image pixels assigned to each inch of printed or displayed size. A 3,000-pixel-wide image at 300 ppi spans 10 inches; printer ink-dot resolution is a different measurement.

Read the guide: Print Photos from Your Phone: Files, Crops and Connections

Reference: Adobe: printed image resolution

Point-to-Point Protocol over Ethernet: carrying PPP sessions inside Ethernet frames, often for subscriber access. The extra encapsulation affects the available packet size; the supported MTU depends on the service and equipment.

Read the guide: PPP and PPPoE: Sessions, Authentication, and Troubleshooting

Reference: PPP over Ethernet (RFC 2516)

Measuring and describing a device's color behavior, commonly in an ICC profile. The profile helps color-management software translate colors between spaces; it must correspond to the device and settings in use.

Read the guide: Color Management for Digital Art and Printing

Reference: International Color Consortium: profiles

Compare: Calibration (color), Color space, Embedded profile

Scanning each frame’s lines in sequence as a complete image, rather than alternating between two interlaced fields. The p in a label such as 720p indicates progressive scanning. Resolution and frame rate describe additional properties, so compare the full format when deciding how to play, edit or convert a recording.

Guide: HDV Format: Identify, Capture and Edit Older HD Video

Reference: Adobe: progressive scanning and noninterlaced frames

Compare: Interlaced video, Frame rate

An agreed set of rules for exchanging information between systems. A protocol specifies behavior or message structure; a connector specifies a physical connection.

The documented history of an artwork's ownership and custody. Dates, identities and gaps matter when assessing that history; provenance contributes evidence alongside examination and other research.

Read the guide: How the Art Business Works: People, Records and Provenance

Reference: Getty: provenance research

Program service data: information accompanying an HD Radio program, such as title and artist text. The station supplies the data and the receiver determines which fields it displays.

Related coverage: HD Radio on an iPhone: Receiver Accessories, Apps, and Streaming

Reference: HD Radio: program service data

Pounds-force per square inch: a unit of pressure, usually written psi or PSI. In a pressure-washer specification it describes pressure at stated operating or test conditions. Read it alongside water flow in GPM and the fitted nozzle; a momentary maximum pressure and a working-pressure rating can describe different conditions.

Guide: Pressure Washers: Match the Machine to the Surface

Reference: NIST: pressure units and conversions (PDF) · Generac: pressure and flow rating conditions (PDF)

Compare: GPM

Physical vapor deposition: forming a coating by transferring material through a vapor phase onto a surface. The process and material determine the resulting film's properties.

Related coverage: Physical Vapor Deposition: Understand and Qualify Thin Films

Quality of service: mechanisms and policies that classify and treat network traffic differently. Prioritization, queueing and resource controls can support service goals, but do not create unlimited link capacity.

A group of four conductors arranged as two pairs in telecommunications cabling. The cable's construction and specification determine how those conductors are used.

Planned processes that provide confidence that requirements will be met. Reviews, documented methods and audits can help prevent recurring quality problems.

Operational checks and activities used to assess and control whether an output meets requirements. Inspection and testing are common examples; acceptance criteria determine what counts as passing.

Isolating a suspected file so that it cannot be used in the usual way while it is assessed. A quarantine report concerns that item; broader checks may still be needed to understand what happened on the system.

Read the guide: Antivirus Protection: What You Need and How to Check It

Reference: Microsoft: virus and threat protection

Compare: Malware, Computer virus, Ransomware

A crystalline mineral composed of silicon dioxide, SiO2. It occurs in many rock types and in several colors; color is only one observation to combine with other identification evidence.

Read the guide: Tonalite: Composition, Formation, and Comparison with Granite

Reference: National Park Service: minerals

Compare: Tonalite, Plagioclase

A clock whose timekeeping uses the regular oscillation of a quartz crystal. Its accuracy depends on the oscillator and conditions such as temperature as well as the clock's design.

The part of a URL introduced by ?, often carrying parameters such as q=radio. Its meaning is defined by the receiving application; parameter names and values need appropriate encoding.

Read the guide: How to Read a URL: Domains, Paths, Queries, and Fragments

Reference: WHATWG URL standard

A secure transport protocol carried over UDP, supporting multiplexed streams, connection establishment and congestion control. HTTP/3 uses QUIC; the use of UDP underneath does not remove QUIC's own delivery and security mechanisms.

Read the guide: OSI Layers in Practice: Follow a Connection, Find a Fault

Reference: QUIC specification (RFC 9000)

Compare: TCP, UDP, TLS

Qualified vendor list: a manufacturer's record of components tested for compatibility with a specified product. For memory, match the exact module or kit and the listed system conditions, including supported module counts. A similar part number is not the same test result, and absence from a QVL does not by itself prove incompatibility.

Guide: RAM Upgrades: Capacity, Compatibility, and Stable Settings

Reference: Corsair: memory compatibility and QVLs · ASUS: example QVL with module-count conditions (PDF)

Compare: DIMM, RAM, CAS latency

A quantity derived from radar echoes that describes scattering by targets. Weather-radar reflectivity is commonly displayed on the logarithmic dBZ scale. Particle size, type and concentration, as well as unwanted echoes, affect the result. Interpret it with other observations when estimating precipitation; Doppler velocity measures a different property, motion along the viewing direction.

Guide: NASA's NPOL Radar: How Scientists Measure Rain and Snow

Reference: National Weather Service: dBZ and reflectivity interpretation

Compare: Doppler effect

Remote Authentication Dial-In User Service: a protocol used by network access equipment to consult a server about authentication, authorization and connection settings. Enterprise Wi-Fi commonly uses it between an access point or controller and a backend service. An Access-Accept response records one successful stage; address assignment and access to the intended application must also work.

Guide: Wireless LAN Authentication: 802.1X, RADIUS and EAP Methods

Reference: RFC 2865: RADIUS access requests and responses

Compare: EAP, Authorization, DHCP

Redundant array of independent disks: a way of organizing multiple drives into one storage array. The chosen layout uses striping, mirroring or parity to balance capacity, performance and tolerance of drive failure; RAID 0 provides no redundancy. Keep a separate recovery plan for deletion, corruption or loss of the whole array.

Guide: RAID Levels Explained: Capacity, Drive Failures, and Recovery

Reference: Linux MD documentation: RAID layouts and failure behavior

Compare: NAS, Backup, Fault tolerance

Random-access memory: the working memory a computer uses for active programs and data. Ordinary system RAM is volatile, so saving work to persistent storage serves a different purpose from adding memory capacity.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: Kingston: memory and storage

Compare: SSD, Byte, Bit

An air-breathing jet engine that uses forward motion to compress incoming air before combustion. It requires incoming airflow at suitable speed rather than a conventional rotating compressor.

Reference: NASA: ramjet and scramjet propulsion

Using a chance-based procedure to assign experimental units to conditions or determine run order. This helps prevent treatment conditions from systematically aligning with other influences, such as measurement order. Random assignment supports a fair comparison within the experiment; representative population sampling addresses the separate question of whom or what the results describe.

Guide: Research Design Tools: Turn a Question into a Testable Experiment

Reference: NIST: completely randomized designs

Compare: Experimental unit, Blocking (experiments), Confounding

Malware or an attack that blocks access to data or systems, often through encryption, while demanding payment. Attacks can also involve stolen data; recovery planning needs to address both system restoration and exposure.

Read the guide: Anti Virus and Malware: Protection, Recovery, and Outbreak Lessons

Reference: CISA: ransomware guide

Compare: Malware, Computer virus, Quarantine (security software)

A camera file containing sensor-derived image data and metadata for later processing. Formats and software support vary; retaining the original file and its editing information allows future reinterpretation of the photograph.

Read the guide: Photo Storage: Organize, Back Up and Recover Your Pictures

The sequence in which content is presented for reading, including through assistive technology. In a PDF, structure tags help determine this sequence. A two-column page should read in a meaningful order instead of jumping between unrelated lines. Check reading order and the tab sequence through interactive controls as separate tasks.

Guide: Accessible PDFs with Adobe Acrobat: Create, Check and Repair

Reference: W3C: PDF reading and tab order

Compare: Tagged PDF, Screen reader, Keyboard focus

Recovery material used to unlock encrypted storage when its usual unlocking method is unavailable. BitLocker, for example, uses a 48-digit recovery key that may be requested after a hardware or security change. Confirm access to the correct recovery material before replacing a drive, and keep it secure separately from that drive.

Guide: Toshiba XG5-P Client NVMe SSD: Compatibility and Upgrade Checks

Reference: Microsoft: finding a BitLocker recovery key

Compare: Authentication, Backup, Restore (data)

A shift of a spectral feature toward longer wavelengths compared with its known emitted wavelength. Redshift z equals observed wavelength divided by emitted wavelength, minus one. Cosmological redshift reflects the expansion of space during light's journey; motion and gravity can also shift light. Inferring cosmic distance or lookback time requires an appropriate model.

Guide: The Most Distant Galaxies: Redshift, Lookback Time and Confirmation

Reference: NASA Hubble: interpreting cosmological redshift

Compare: Spectrum (light), Lookback time, Doppler effect

Cooking a liquid so some evaporates, leaving a smaller, more concentrated amount. A reduced stock or sauce can gain stronger flavor and a thicker consistency, depending on what remains in it. Reduction removes liquid; it is different from thickening by adding starch. Taste again afterward because salt and other retained ingredients have also become more concentrated.

Guide: Culinary Vinegar: Choose a Type and Balance a Dish

Reference: Professional Cooking: sauce reduction, chapter 9 (PDF)

Compare: Emulsion, Sweating (cooking)

The rearrangement of content to fit the available viewing space as a window narrows or text is enlarged. Paragraphs wrap and sections can stack while retaining their meaning and usable controls. This lets readers follow ordinary text without scrolling sideways for each line; maps and some other two-dimensional content need separate treatment.

Guide: Website Accessibility Check: A Practical First Audit

Reference: W3C: Reflow

Compare: Reading order, Contrast ratio (accessibility)

The frequency at which a display refreshes its image, measured in hertz (Hz). A 60 Hz mode refreshes 60 times per second. Compare this with the content's frame rate: a high refresh-rate display still needs suitable frames, settings and a supported connection to deliver the intended motion experience.

Guide: Choosing a Graphics Card: Workloads, VRAM, Power, and Fit

Reference: Microsoft: display refresh rate

Compare: Frame rate, HDMI

Software testing after a change to check whether behavior that previously worked has been unintentionally affected. Relevant checks can be automated or manual and should cover meaningful user outcomes. After repairing a form label, for example, check that repeated fields still have distinct usable names and that the form’s other essential interactions continue to work.

Guide: Accessibility Evaluation and Repair: From Finding to Retest

Reference: ISTQB: selecting regression tests after changes (PDF)

Compare: Form label, Accessible name, Interoperability

Sea-surface height measured relative to a local land reference. Changes reflect both the water level and vertical movement of the land: sinking land can increase local relative rise, while uplift can reduce it. A tide-gauge trend describes an observed location and period; future planning also requires suitable scenarios and their assumptions.

Guide: Sea Level Rising: Read Local Trends and Future Scenarios

Reference: NOAA: relative sea level and land motion

Compare: Watershed, Geographic coordinates

Closeness of repeated measurement results under specified repeatability conditions: the same procedure, operator, measuring system, operating conditions and location over a short period. A small spread indicates good repeatability for those conditions. Consistently biased readings can still cluster tightly, so repeatability and agreement with a reference value require separate checks.

Guide: Pipetting: Improve Accuracy, Precision, and Repeatability

Reference: JCGM VIM: measurement repeatability · JCGM VIM: repeatability conditions

Compare: Standard deviation, Coefficient of variation, Computational reproducibility

Maintaining another copy of stored data by copying changes to a second location or system. Synchronous replication waits for the destination to acknowledge a write; asynchronous replication can leave the destination behind the source. Replicated deletions or corruption can affect both copies, so plan retained recovery versions and independent backups alongside replication.

Guide: Storage Mirroring and Replication: Failure Scenarios and Recovery Tests

Reference: Microsoft: synchronous and asynchronous storage replication

Compare: RPO, RTO, Snapshot (storage), Backup

Returning files or a system from a saved backup to a usable location or state. A restore may recover one document, an earlier version or an entire system, depending on the backup. Opening recovered files and checking required applications tests whether the saved copy meets the recovery need.

Guide: Toshiba XG5-P Client NVMe SSD: Compatibility and Upgrade Checks

Reference: Microsoft: backup, restore and recovery

Compare: Backup, Checksum, Recovery key (device encryption)

The elapsed time between sample injection and the position of a component's peak in a chromatogram, commonly measured at the peak maximum. It depends on the separation method and operating conditions. Comparing retention times with suitable standards can support identification, while overlapping or coeluting components require additional evidence.

Guide: Mass Spectrometry: Read the Signal and Understand the Evidence

Reference: Shimadzu: retention-time parameters

Compare: Chromatography, Mass spectrometry, Mass-to-charge ratio

Radio-frequency identification: using radio communication between a reader and a tag to identify or obtain information about an item. Tag type, frequency, placement and surroundings affect the read.

Related coverage: RFID Guides: Technology, Workflows, and Applications

Renewable Fuel Standard, a U.S. program governing renewable-fuel obligations in transportation fuel. Requirements depend on the applicable year and rules; use EPA's current program information for those details.

Related coverage: Cellulosic Biofuel Costs: Evaluate Yield, Scale and Production Claims

Reference: EPA: Renewable Fuel Standard

Radio network controller: equipment or a network function managing radio-access resources in certain cellular architectures. Its responsibilities depend on the network technology and generation.

Related coverage: EV-DO Rev A release 8

A readout method that records different image rows at slightly different times. Fast subject or camera motion can therefore appear skewed, bent or banded; readout speed and lighting conditions affect the artifact.

Read the guide: CMOS Image Sensors: Size, Pixels, Noise and Shutter Readout

Reference: Sony: rolling shutter

A router component that performs control functions such as maintaining routing information. How control and forwarding are divided depends on the router's architecture.

A device or software function that forwards packets between networks using forwarding information. Its interface support and configuration determine which networks it connects.

Recovery point objective: the maximum acceptable period of data loss after an outage, expressed as time. A five-minute RPO means planning to recover data no more than five minutes behind the disruption. Measure the latest usable recovered data to check the objective; backup frequency alone does not establish the achieved result.

Guide: Storage Mirroring and Replication: Failure Scenarios and Recovery Tests

Reference: Microsoft: recovery point and recovery time objectives

Compare: RTO, Backup, Snapshot (storage)

Rapid prototyping platform, a term used in the linked prototyping-equipment coverage. Identify the actual manufacturing process and machine when interpreting a platform's claimed capabilities.

Related coverage: TAK Photo-Printer Prototyping: From Image Processing to a Finished Print

A standard family for serial communication interfaces, including electrical signaling between equipment. RS-232 signaling differs from the low-voltage logic used by many microcontroller UART pins, so an appropriate interface circuit may be required. Verify voltage levels, connector pinout, transmit/receive roles and handshake wiring from both devices’ documentation before connecting them.

Guide: Bluetooth Serial Adapters: Compatibility, Setup, and Testing

Reference: Texas Instruments: translating RS-232 and logic-level signals

Compare: SPP, Baud rate, Flow control

Received Signal Strength Indicator: a receiver’s reported indication of the strength of a received radio signal. Many tools express it in dBm, while reporting scales and measurement details depend on the technology and implementation. Compare readings under consistent conditions alongside noise, packet delivery and application performance; signal strength alone gives an incomplete picture of link quality.

Guide: Bluetooth Transceivers: Radio Range, Antennas, and Link Budgets

Reference: Silicon Labs: a Bluetooth RSSI measurement and its units

Compare: dBm, Signal-to-noise ratio, Throughput

Rotating shadowband spectroradiometer: an instrument that uses a moving shadowband and spectral measurements to study sunlight components. Its calibration and measurement geometry matter to the resulting data.

Reference: ARM: rotating shadowband spectroradiometer (PDF)

Really Simple Syndication, also associated with the name Rich Site Summary: a family of web-feed formats for distributing updates. A feed reader can follow newly published items without visiting each page individually.

Related coverage: Web Feeds

Real-time kinematic positioning: a GNSS method that combines satellite carrier-phase measurements with timely reference-station or network correction data. It can support very precise positioning when the receiver resolves the carrier ambiguities and conditions are suitable. Check solution status, correction availability, antenna setup and surroundings before relying on a reported position.

Guide: GPS Chipsets and GNSS Modules: Selection and Integration

Reference: u-blox: high-precision GNSS and RTK

Compare: GNSS, GPS, DGPS

Recovery time objective: the maximum acceptable time for a defined service to be unavailable after a disruption. Specify what counts as working again, such as completing an application transaction, and measure recovery against that endpoint. RTO concerns downtime; RPO concerns how much recent data can be lost.

Guide: Storage Mirroring and Replication: Failure Scenarios and Recovery Tests

Reference: Microsoft: recovery point and recovery time objectives

Compare: RPO, Availability, Restore (data)

Real-time operating system: an operating system designed to support tasks with defined timing requirements. Meeting a deadline depends on the whole configured system, including applications and hardware.

Related coverage: Avionics Computers: Real-Time Work, Partitioning, and Assurance

Variation in a rotating tool or surface relative to its intended axis of rotation. Radial runout is measured across the axis; axial runout is measured along it. A wobbling drill or poorly seated bit can contribute to an uneven hole. Runout is a geometric condition, distinct from placing an otherwise accurate hole in the wrong location.

Guide: Drill Bits: Match the Material, Hole and Drill

Reference: Mitutoyo: circular and total runout (PDF)

Compare: Chuck, Collet, Shank (tool)

A classification of an oil's flow behavior under specified temperature conditions, written as a complete grade such as 0W-20. The viscosity grade is one part of selecting engine oil. Match it together with the required performance category and any manufacturer specification in the manual for the exact vehicle and engine.

Guide: Motor Oil: Match the Specification to Your Engine

Reference: API: motor-oil viscosity grades and performance markings (PDF)

Selective Availability, intentional degradation formerly applied to the publicly available GPS signal. The U.S. government discontinued its use in May 2000.

Related coverage: GPS Guides: Navigation, Receivers, Mapping, and Tracking

Reference: GPS.gov: Selective Availability

The number of samples taken or represented per second for a signal, expressed in hertz. In audio, 48 kHz means 48,000 samples per second per channel. Sample rate helps determine the frequency range that can be represented; bit depth and the encoded bit rate describe other aspects of the data.

Guide: Speech codecs: why phone-call quality changes

Reference: RFC 4867: sampling frequencies and encoded speech

Compare: PCM (audio), Bit rate, Codec

Serial ATA: an interface family for connecting storage devices such as hard drives and SSDs to a host. SATA support is a compatibility requirement for the drive, connection and enclosure. M.2 describes a module format that can carry different interfaces, so check whether an M.2 product uses SATA or PCIe/NVMe.

Guide: Toshiba XG5-P Client NVMe SSD: Compatibility and Upgrade Checks

Reference: SATA-IO: the SATA ecosystem

Compare: M.2, NVMe, SSD

To cook food quickly in a hot, shallow pan with a small amount of fat, commonly using small or thin pieces. Give the food enough space for contact with the pan and for moisture to escape. Adjust heat to the ingredients and cookware; gentle sweating instead aims to soften aromatics with little browning.

Guide: Sautéing: Heat, Pan Space and Three Useful Methods

Reference: Escoffier teaching text: sautéing and pan-frying (PDF)

Small Business Innovation Research, a U.S. program supporting small-business research and development with commercialization potential. Eligibility and open opportunities are set by current program and agency rules.

Related coverage: Composite Ballistic Screens: The DDG-1000 Development Case

Reference: SBIR and STTR programs

The ability of a system to accommodate a larger workload or deployment. A useful claim identifies what grows, which resources must be added and how performance changes.

Checking a document against a defined set of structural and data rules, such as an XML schema. It can catch invalid structure or values; authorization, safe parsing and application-level checks address other requirements.

Read the guide: Web Service Security: Access, XML Parsing, and Resource Limits

Reference: OWASP: web-service security

Supersonic-combustion ramjet: an air-breathing engine in which airflow remains supersonic through the combustion region. It is a particular engine concept within high-speed propulsion.

Related coverage: Ramjet definition

Reference: NASA: ramjet and scramjet propulsion

Assistive software that presents digital content and interface information through synthesized speech or refreshable braille. It lets users navigate structures such as headings, links and form controls. Meaningful markup, labels and reading order help it communicate the page; converting a picture of text with OCR supplies only one part of that structure.

Guide: Accessible PDFs with Adobe Acrobat: Create, Check and Repair

Reference: W3C: assistive tools and techniques

Compare: Alternative text, HTML, OCR

Service Delivery Card, SanDisk's product name for an operator-oriented storage-card system. Its service and device claims belong to that implementation and period.

Related coverage: Service delivery card

Software development kit: tools, libraries, documentation and examples provided to help developers build for a platform or service. Compatibility depends on the SDK version and its target environment.

Related coverage: On2 DirectShow VP8 SDK

Rock formed by the accumulation and consolidation of sediment or by material precipitating from solution. Layers, grain sizes and fossils can provide evidence about its formation environment.

Read the guide: Rocks and Minerals: A Guide to Observing and Understanding Them

Reference: National Park Service: rocks

Dividing a network into areas with controlled communication between them. Enforced boundaries can limit how far an intrusion spreads; the result depends on the actual access rules and paths between segments.

Read the guide: Anti Virus and Malware: Protection, Recovery, and Outbreak Lessons

Reference: CISA: ransomware guide

Waves of energy traveling through the Earth or along its surface, generated by earthquakes and other sources. Differences in wave speed and behavior help scientists infer properties of the Earth's interior.

Read the guide: What Rocks Reveal About Earth's Interior

Reference: USGS: inside the Earth

Using HTML elements according to the meaning and role of the content they represent, such as headings for section titles, buttons for actions and tables for tabular data. Appropriate native structure helps browsers and assistive technology interpret a page. Preserve a coherent reading order and verify actual interaction behavior alongside the markup.

Guide: FrontPage Accessibility: Modernize an Older Website

Reference: W3C: meaningful page structure

Compare: HTML, Reading order, Accessible name

How long a sensor takes to respond to a specified change in its input under stated conditions. For a step-response specification, this can be the time until the indication settles within stated limits around its final value. The logger's sampling interval is a separate setting: frequent readings of a slow probe can still miss a brief event.

Guide: Data Loggers: Plan a Measurement You Can Trust

Reference: JCGM VIM: step response time

Compare: Sample rate, Aliasing (sampling), Measurement resolution

Single-ended primary-inductor converter: a DC-to-DC converter topology that can produce an output voltage above or below its input voltage. Component ratings and the specific circuit determine usable operation.

Related coverage: SEPIC Converters: Understand Operation and Design Tradeoffs

A set of colors arranged to communicate an ordered progression, such as low to high values on a map. A light-to-dark progression is common; hue can change as well. Choose readable steps that preserve the order, and define the numeric class boundaries separately so each color has a clear meaning in the legend.

Guide: Map Colors with ColorBrewer: Choose, Classify, and Check

Reference: ColorBrewer: sequential, diverging and qualitative color schemes

Compare: Diverging color scheme, Class interval (mapping), Choropleth map

Standard Generalized Markup Language: a standard for defining markup languages for structured documents. It is part of the historical background of HTML and XML; modern HTML has its own parsing rules.

Read the guide: SGML, XML, and HTML: Understanding Structured Documents

Reference: W3C introduction to SGML

The part of a bit or cutting tool that fits into the tool holder, such as a drill chuck. Its diameter and shape determine the required holding interface. The cutting diameter can differ from the shank diameter, so check both, together with the tool's rated capacity and the accessory's intended operation.

Guide: Drill Bits: Match the Material, Hole and Drill

Reference: Bosch: drill shank shapes and tool compatibility · Bosch: straight and reduced-shank bits (PDF)

Compare: Chuck

The duration of an exposure, usually expressed in seconds or fractions of a second. A shorter exposure gathers less light at the same aperture and can reduce motion blur; a longer exposure allows more light and more movement. Rolling shutter describes how the image is read out, a separate timing property.

Guide: Better Phone Photography: Override Auto Exposure on iPhone and Android

Reference: Nikon: exposure and shutter speed

Compare: Rolling shutter, Exposure compensation

A separate file stored alongside an image to hold information such as metadata or editing instructions. Keeping the image and its associated sidecar together helps preserve edits when moving or backing up a photo collection.

Read the guide: Photo Storage: Organize, Back Up and Recover Your Pictures

The ratio of signal power to noise power for a stated measurement, commonly abbreviated SNR and expressed in decibels. When both powers are measured in dBm under comparable conditions, subtract the noise reading from the signal reading to obtain SNR in dB. Record the measurement conditions and available noise evidence before using it to assess a wireless link.

Guide: Wi-Fi Site Survey: Map Coverage and Validate Real Tasks

Reference: Cisco Meraki: signal-to-noise ratio and wireless measurements

Compare: RSSI, dBm, Throughput

A shape read mainly through its outer contour, often as a dark or flat area against a contrasting background. In an artwork, silhouettes can clarify figures and organize relationships even when interior detail is limited.

Read the guide: How to Look at Seurat’s La Grande Jatte

Reference: Art Institute of Chicago: La Grande Jatte

Sport Integration System, H2O Audio's name for an accessory-mounting system in period iPod coverage. Its fit and intended uses belong to the documented accessory models.

Related coverage: Sports music system

A retained view of stored data at a particular point in time, useful for retrieving an earlier file version or state. Its recovery value depends on the system, retention and access controls. A snapshot kept only on the same failed or inaccessible storage can share that storage's loss, so assess independent backup separately.

Guide: Storage Mirroring and Replication: Failure Scenarios and Recovery Tests

Reference: Microsoft: file-share snapshots and their protection limits

Compare: Backup, Restore (data), RPO

System on a chip: an integrated circuit combining several major system functions, such as processing and interfaces. The functions included vary with the intended device.

Related coverage: Digital Media Processors: Decode, Scale, Encode and Display Video

A software change supplied to correct a defect, vulnerability or other identified problem. A security patch addresses a security issue; software updates can also add features. Confirm that the fix applies to the installed product and version, then verify installation and any required restart before considering the issue addressed.

Guide: Zotob: What the Patch-to-Outbreak Timeline Teaches

Reference: NIST: patch

Compare: Malware, Computer virus

Synchronous Optical Network, a standardized optical transport system associated with North American telecommunications. Interpreting an inherited circuit requires its line rate, payload, timing and handoff details.

The spatial detail an image can distinguish. In Earth imagery it is often described using ground pixel spacing, but sharpness, blur and noise also affect what can be resolved. Compare the sensor and processed product as well as pixel size; closely spaced samples alone do not guarantee that small features are distinguishable.

Guide: Yangtze River: From Drainage Basin to Sediment Plume

Reference: USGS: spatial data quality and image sharpness

Compare: Ground sample distance, Megapixel, PPI

The electrical opposition a speaker presents to an amplifier’s alternating output, expressed in ohms. It varies with frequency; the nominal rating summarizes a changing load. Use the speaker and amplifier specifications together when checking compatibility, including relevant minimum-impedance limits and permitted speaker arrangements.

Guide: Digital Audio Amplifiers: Class D, Power, and Speaker Matching

Reference: Yamaha: speaker impedance and nominal ratings

Compare: Speaker sensitivity, AV receiver

A measure of a speaker’s sound-pressure output at a stated distance for a specified input, commonly reported in decibels at one meter. Compare the reference conditions: ratings based on one watt and on 2.83 volts can differ with impedance. Sensitivity helps estimate output requirements; it is separate from maximum power handling.

Guide: Digital Audio Amplifiers: Class D, Power, and Speaker Matching

Reference: Yamaha: sensitivity and amplifier power ratings

Compare: Speaker impedance, AV receiver

A selected range of wavelengths measured by an imaging sensor or admitted by a filter. Different bands can reveal different properties of vegetation, water, rock or emitted heat. Check the sensor's wavelength ranges before comparing band numbers, and keep the measured band separate from the visible color assigned to it in a displayed image.

Guide: Earth Imaging: Choose and Compare Satellite and Aerial Images

Reference: NASA Landsat: spectral bands and their applications

Compare: Surface reflectance, Spectrum (light), Spatial resolution (imagery)

A representation of light separated by wavelength, frequency or photon energy. An astronomical spectrum shows how a measured quantity, such as brightness or the fraction of starlight blocked, changes across that range. Its features can help investigate composition or motion. Read the axes, units and uncertainty before interpreting a peak or dip.

Guide: James Webb Space Telescope: How to Read Its Images and Spectra

Reference: NASA Webb: spectroscopy and scientific instruments

Compare: Spectral band, Redshift, Transit (astronomy)

Sender Policy Framework: an email mechanism that lets a domain publish which hosts may use its name in the SMTP envelope sender or HELO identity. A receiving server checks the sending host against that policy. The identity checked can differ from the visible From address; use DMARC alignment to connect authentication to that address’s domain.

Guide: Email Sender Authentication: SPF, DKIM, DMARC, and Their Limits

Reference: RFC 7208: Sender Policy Framework

Compare: DKIM, DMARC, DNS

Serial Port Profile: a Bluetooth Classic profile that uses RFCOMM to emulate a serial cable connection between devices. A compatible host may expose this as a virtual serial port. Check the adapter’s role and host support; a Bluetooth LE service described as UART or serial typically uses a different GATT-based interface.

Guide: Bluetooth Serial Adapters: Compatibility, Setup, and Testing

Reference: Bluetooth SIG: Serial Port Profile

Compare: RS-232, GATT, Bluetooth profile

Software that covertly collects information about a person or organization without their knowledge or authorization. It may monitor activity or transmit collected data to another party. The collection behavior and permissions are the key questions when investigating it; symptoms such as a slow device can have many other causes.

Guide: Spyware: Warning Signs, Exposure, and Recovery

Reference: NIST: spyware

Compare: Malware, Information security, Authorization

Structured Query Language: a language for defining, querying and changing data in relational database systems. Products support different dialects; an application should pass untrusted values through parameters rather than concatenate them into SQL text.

Read the guide: SQL Explained with Queries You Can Follow

Reference: SQLite SELECT documentation

Solid-state drive: persistent storage that uses solid-state memory, commonly flash. Capacity, interface and workload affect its usefulness; an SSD stores files while system RAM holds active working data.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: Kingston: memory and storage

Compare: RAM, Byte, Bit

Service Set Identifier: the name used to identify a Wi-Fi network. Several access points can advertise the same SSID, and an unrelated transmitter can copy the name. Use the venue’s official connection instructions and expected security settings when choosing a network; the displayed name alone does not establish who operates it.

Guide: Airport Wi-Fi: Find the Official Network and Get Connected

Reference: Microsoft: the 802.11 service set identifier

Compare: Wi-Fi, Captive portal

Super Self Refresh, an Elpida name for a memory power-saving feature in historical DDR SDRAM coverage. It describes that product feature rather than a universal capability of all memory modules.

Related coverage: DDR SDRAM: Transfers, Refresh, and Legacy Compatibility

A measure of how widely values vary around their mean, expressed in the same units as the observations. The usual sample calculation squares the deviations from the sample mean, sums them, divides by n − 1, then takes the square root. Population calculations use a different convention. Standard deviation describes spread; standard error describes uncertainty in an estimated statistic.

Guide: Pipetting: Improve Accuracy, Precision, and Repeatability

Reference: NIST: sample standard deviation (PDF)

Compare: Coefficient of variation, Repeatability (measurement)

The rise in coastal water level caused by a storm above the predicted astronomical tide, driven mainly by winds pushing water toward the coast. Storm tide combines surge with the tide; waves add further effects. Read surge guidance separately from a hurricane's wind category and center track, using current local evacuation information for decisions.

Guide: Hurricanes: Read the Forecast and Prepare for Each Hazard

Reference: National Hurricane Center: storm surge and storm tide

Compare: Forecast cone

Small Business Technology Transfer, a U.S. research program involving collaboration between small businesses and research institutions. Current agency rules define participation and funding opportunities.

Related coverage: Ferrium C61 C64 alloys

Reference: SBIR and STTR programs

An estimate of how a surface reflects incoming light within a wavelength band. Satellite surface-reflectance products correct measurements for atmospheric scattering and absorption to support comparisons of surface properties. Interpretation still depends on the product, viewing conditions and quality flags; apply its documented scaling and screen clouds and shadows before comparing numerical values.

Guide: Earth Imaging: Choose and Compare Satellite and Aerial Images

Reference: NASA LAADS DAAC: atmospherically corrected surface reflectance

Compare: Spectral band, Spatial resolution (imagery)

Software virtual network, a phrase used in Scalable Network Technologies' historical communications-simulation coverage. Here it means a modeled network environment; the model's assumptions bound what its results establish.

Related coverage: Software Virtual Networks: Simulation, Emulation, and Model Limits

Gently cooking vegetables in a small amount of fat until they soften and release moisture, while keeping browning minimal. Often used for onions and other aromatics at the start of a soup or sauce. Follow the recipe's texture and color cues; sautéing typically uses a hotter pan for quicker cooking.

Guide: Sautéing: Heat, Pan Space and Three Useful Methods

Reference: Escoffier teaching text: sweating and dry-heat methods (PDF)

Compare: Sauté

The internal interconnection that carries traffic between a device's input and output interfaces. Its architecture and capacity contribute to how the device handles simultaneous traffic.

A PDF containing a structure tree that identifies content roles and relationships, such as headings, paragraphs, lists and tables. Assistive technology uses this structure to interpret and navigate the document. Useful tags need accurate roles and reading order; an accessibility review also checks matters such as image alternatives, language and form labels.

Guide: Accessible PDFs with Adobe Acrobat: Create, Check and Repair

Reference: Adobe: creating accessible PDFs

Compare: Reading order, Screen reader, OCR

Troubled Asset Relief Program, the U.S. financial-crisis program established in 2008. Historical repayment and investment reports refer to specific program transactions and dates.

Related coverage: Bank of America repays TARP

Reference: U.S. Treasury: TARP

Terabits per second: one trillion bits per second. It describes a data rate, not an amount of storage or a guaranteed application-transfer speed.

Transmission Control Protocol: a transport protocol providing an ordered byte stream with mechanisms for reliability, flow control and congestion control. Applications add their own message boundaries above that stream.

Read the guide: OSI Layers in Practice: Follow a Connection, Find a Fault

Reference: TCP specification (RFC 9293)

Compare: UDP, QUIC, TLS

Damage left when wood fibers lift, split or break away instead of being cleanly cut, producing ragged edges or depressions below the intended surface. Grain direction, unsupported fibers, cutting-edge condition and the amount removed can contribute. Tear-out is different from a burned surface, so diagnosing it requires more than changing tool speed.

Guide: Router Bits: Match the Profile, Shank and Cut

Reference: Lee Valley: wood-fiber tear-out and grain direction

Compare: Runout, Shank (tool)

A binary unit of data equal to 2^40 bytes, or 1,099,511,627,776 bytes, written TiB. A decimal terabyte (TB) is 1,000,000,000,000 bytes. Check which unit a storage specification or display uses before comparing capacity; reserved space, formatting and redundancy can reduce the capacity available for files further.

Guide: Network Attached Storage: Capacity, Sharing, and Recovery

Reference: NIST: prefixes for binary multiples

Compare: Byte, NAS, RAID

Trusted Exchange Framework and Common Agreement, a U.S. framework supporting exchange of electronic health information among participating networks. Technical requirements and permitted exchange purposes belong to the applicable framework documents.

Reference: HealthIT: TEFCA

Material placed between a heat-producing component and a cooling surface to improve heat transfer by filling gaps that would otherwise contain insulating air. Thermal paste and thermal pads are examples. The required material, thickness and application depend on the assembly; TIM complements correct mechanical contact rather than replacing it.

Guide: How Heat Sinks Work: Diagnose Cooling with Better Measurements

Reference: Boyd: thermal interface materials

Compare: Heat sink, Heat pipe, Thermal throttling

A device's reduction of performance to control temperature, such as a processor lowering its operating frequency or voltage when thermal controls engage. The trigger and response depend on the device and system design. A lower clock speed alone does not establish thermal throttling: workload changes and power limits can also change performance.

Guide: How Heat Sinks Work: Diagnose Cooling with Better Measurements

Reference: Intel: processor thermal management, section 5 (PDF)

Compare: Heat sink, GPU, Firmware

A client computer designed to obtain much of its application processing and storage from remote servers over a network. It still handles local tasks such as displaying the session and accepting input. Supported services, peripherals and any offline capability depend on its operating system, client software and deployment; the label alone does not establish compatibility.

Guide: Network Clients: Thin Clients, Remote Desktops, and Terminal Workflows

Reference: AWS: thin clients and centralized computing

Compare: Information system, Interoperability

The rate of data successfully transferred across a defined boundary during a measured interval. Application payload throughput can be lower than the link's capacity because of overhead, congestion and endpoint limits; state what was counted.

Read the guide: Technology Terms That Help You Read Product Specifications

Compare: Bandwidth (network capacity), Latency

A system for identifying positions in recorded media, commonly displayed as hours, minutes, seconds and frames for video. Editors use it to locate material, align clips and record edit points. Interpret a value with its frame rate and counting convention, and distinguish source timecode from project timecode and a file’s creation timestamp.

Guide: DV Disk Recorders: Transfer and Check FireStore Footage

Reference: Apple: locating and editing video using timecode

Compare: Frame rate, Container (media file), FireWire

Transport Layer Security: a protocol for protecting communications against eavesdropping and tampering and authenticating peers as configured. HTTPS uses TLS; certificate checks and the negotiated protocol version are part of the connection's security.

Read the guide: OSI Layers in Practice: Follow a Connection, Find a Fault

Reference: TLS 1.3 (RFC 8446)

Compare: TCP, UDP, QUIC

A coarse-grained igneous rock rich in quartz and plagioclase, with relatively little alkali feldspar. Formal classification uses mineral proportions; visual resemblance to granite alone is insufficient to identify a specimen.

Read the guide: Tonalite: Composition, Formation, and Comparison with Granite

Reference: British Geological Survey: tonalite

Compare: Quartz, Plagioclase

The downward load a trailer applies at its coupling to the towing vehicle. It contributes to the vehicle's load and affects axle loading and hitch requirements. Measure and assess it using the applicable vehicle, trailer and hitch guidance; the permitted amount and loading balance depend on the specific combination.

Guide: 2008 Nissan Titan: Verify Configuration, Payload and Towing Limits

Reference: Nissan: trailer tongue load and load distribution (2008 Titan manual, PDF)

Compare: Payload (vehicle), GVWR, GAWR

The turning effect of a force about an axis. Its magnitude depends on the force and the perpendicular distance from the axis to the force's line of action. Common units include N·m, ft-lb and in-lb. For fastening, use the exact assembly's specified torque, units and conditions; torque and joint clamping force are different quantities.

Guide: Torque Wrenches: Specifications, Units and Controlled Tightening

Reference: NASA Glenn: torque and perpendicular lever arm

Total parenteral nutrition: providing a person's nutritional requirements through an intravenous route. It is a clinical treatment managed by a care team rather than a general substitute for ordinary eating.

Related coverage: TPN Explained: Nutrition Through a Vein and Planning for Home

Reference: National Cancer Institute: TPN

Converting encoded media by decoding it and encoding a new representation, such as making a smaller viewing copy from an editing master. The chosen codec and settings determine what is preserved or changed. Moving the same encoded streams into a different container is rewrapping; that operation can avoid a new compression generation.

Guide: Lossless Video Codecs: Masters, Editing and Viewing Copies

Reference: FFmpeg: transcoding and stream copying

Compare: Codec, Container (media file), Lossy compression

The apparent passage of one celestial object across the face of another from the observer's viewpoint. An exoplanet transiting its star blocks a small fraction of the star's light. Measuring that change over time helps study the system; measuring its wavelength dependence can probe the planet's atmosphere when supported by suitable observations and modeling.

Guide: Exoplanet Carbon Dioxide: How to Evaluate an Atmospheric Detection

Reference: NASA Webb: starlight blocked during an exoplanet transit

Compare: Light curve, Spectrum (light)

Torque Shift System, the name used for a variable-length intake system in MV Agusta F4 coverage. Its implementation and maintenance requirements belong to the specific motorcycle model.

Related coverage: 2010 MV Agusta F4: Model Reference and Buyer Preparation

Universal companion document, guidance for implementing a specified check-image exchange standard. The document's version and the underlying X9 standard are necessary parts of the reference.

Related coverage: Check images

Universal Description, Discovery and Integration: a specification for registries describing businesses and web services. It belongs to the service-discovery architecture used by the particular system.

Related coverage: UDDI

User Datagram Protocol: a transport protocol carrying individual datagrams with limited built-in services. Applications or higher-level protocols decide how to handle loss, ordering and congestion when those features are needed.

Read the guide: OSI Layers in Practice: Follow a Connection, Find a Fault

Reference: UDP specification (RFC 768)

Compare: TCP, QUIC, TLS

Universal Flash Storage: a JEDEC standard family for communication between a host and flash-storage device. It defines an interface and related commands used in devices such as phones. NAND describes the underlying memory technology; UFS describes how storage communicates. Compare the actual device and host capabilities when interpreting a version or performance claim.

Guide: 64-Layer 3D NAND Explained: Flash Memory and UFS

Reference: Linux kernel documentation: Universal Flash Storage architecture

Compare: NAND flash, NVMe, SSD

Universal Mobile Telecommunications System, a third-generation mobile communications system. Supported bands, network operation and service configuration determine whether a particular device can use it.

Related coverage: UMTS : Universal Mobile Telecommunications System

Resampling an image or video to a larger pixel grid for display or output. Processing can improve its presentation, but the source's recorded detail remains a constraint on the result.

Read the guide: How to Play DVDs Today: TVs, Computers, Consoles, and Portable Players

Uniform Resource Locator: an address that identifies a resource and how to access it. A web URL can include a scheme, host, path, query string and fragment; each part has a different role.

Read the guide: How to Read a URL: Domains, Paths, Queries, and Fragments

Reference: WHATWG URL standard

A reversible USB connector type, also called USB Type-C. The connector shape alone does not establish supported data speed, display output or charging power; check the capabilities of the port, cable and device together.

Read the guide: Technology Terms That Help You Read Product Specifications

Reference: USB-IF: USB Type-C

A USB specification for negotiating power between compatible connected devices. The supported source, receiving device and cable together determine the usable charging arrangement. Check the laptop’s input requirements and the supply’s available power modes; a USB-C connector identifies the plug shape while Power Delivery describes power capabilities.

Guide: Laptop Batteries and Power Banks: Compatibility, Health, and Runtime

Reference: USB-IF: USB Power Delivery

Compare: USB-C, Watt, Pass-through charging

Coordinated Universal Time, the international time reference based on atomic time with adjustments relating it to Earth's rotation. UTC itself does not shift for daylight saving time; local civil time applies its own offset.

Reference: NIST: UTC and other time scales

Displaying elevation differences at an enlarged scale relative to horizontal distances in a terrain view or profile. An exaggeration factor of 3 makes a given relief appear three times as tall relative to the horizontal scale. It helps reveal subtle terrain; record the factor before judging slope or landform shape from the display.

Guide: Reading 3D Maps: Terrain, Tilt, and Perspective

Reference: Esri: elevation surfaces and vertical exaggeration

Compare: Map scale

Virtual local area network: a logical separation of a switched network into distinct link-layer broadcast domains. VLAN configuration and routing or firewall policies together determine how devices in different VLANs can communicate.

Read the guide: IEEE 802 Explained: Read Ethernet, Wi-Fi, and VLAN Specifications

Reference: IEEE 802.1Q bridges and VLANs

Voice over Internet Protocol: carrying voice communication as data over IP networks. Call quality depends on the endpoints, network path, delay and packet delivery as well as the service.

Related coverage: VoIP Guides: Calls, Equipment, SIP, and Operations

Voice over LTE: an operator voice service carried as IP packets over an LTE mobile network using IMS. The handset, its configuration and the operator must support the service together. A phone that connects for LTE data can still lack the supported voice setup required for calls.

Guide: 3G phones: compatibility, shutdowns and useful reuse

Reference: GSMA: VoLTE

Compare: LTE, IMS, VoIP

Video RAM: memory used to hold graphics resources such as textures and frame buffers, as well as data for supported GPU computing tasks. A discrete graphics card typically has dedicated video memory. Capacity helps determine whether a workload fits; compare memory bandwidth, the GPU and software support alongside the capacity figure.

Guide: Choosing a Graphics Card: Workloads, VRAM, Power, and Fit

Reference: AMD: video memory and graphics workloads

Compare: GPU, RAM, PCIe

Wide area network: connecting devices or local networks across a wider geographical area. Links and services can have different providers, capacities and operational responsibilities.

Related coverage: LAN definition

An area of land whose surface runoff drains toward a specified common outlet, such as a stream junction, lake outlet or river mouth. Smaller watersheds can lie within larger ones. Identify the outlet and boundary when comparing river observations, because upstream land and tributaries contribute to conditions downstream.

Guide: Yangtze River: From Drainage Basin to Sediment Plume

Reference: USGS: watersheds and drainage basins

Compare: Relative sea level, Spatial resolution (imagery)

The SI unit of power, equal to one joule per second, with the symbol W. It describes how quickly energy is transferred or used. A kilowatt is 1,000 watts. An appliance’s watt rating and its operating time together help estimate energy use; cycling controls and operating conditions affect the actual total.

Guide: How Fast Should a Kettle Boil? Comparing Time and Water Volume

Reference: NIST: watt as a unit of power

Compare: Kilowatt-hour, Induction heating

An adjustment that accounts for the color of the illumination so neutral subjects can appear neutral, or gives an image an intentional warmer or cooler rendering. Cameras offer automatic, preset and custom controls. Mixed lighting can require a compromise because one setting may not suit every part of the scene.

Guide: Better Phone Photography: Override Auto Exposure on iPhone and Android

Reference: Nikon: setting white balance

Compare: Color space, RAW image file, Calibration (color)

Cells of the immune system that help defend the body against infection and other threats. Major groups include granulocytes, monocytes and lymphocytes; laboratory counts are interpreted in their clinical context.

Reference: National Cancer Institute: white blood cell

Wireless local networking based on the IEEE 802.11 standards, commonly connecting devices to an access point. The Wi-Fi link and the network’s onward internet connection are separate parts of the route. A strong Wi-Fi signal can coexist with a slow or unavailable internet service.

Guide: Indoor 5G: Diagnose Weak Coverage and Improve Your Connection

Reference: IEEE: wireless LAN standards

Compare: LAN, Ethernet, Router

A Wi-Fi connection method that lets compatible devices communicate directly without a separate wireless access point or router. A supported printer can use it to receive a print job from a phone or computer. Follow the specific devices’ setup instructions and check how the connection affects any separate internet access.

Guide: Bluetooth Printer Adapters: What Works and What to Use Instead

Reference: Epson: direct device connections without a wireless router

Compare: Wi-Fi, SSID

Worldwide Interoperability for Microwave Access, an ecosystem associated with IEEE 802.16 wireless broadband systems. Equipment and service compatibility depend on the profile, frequency band and implementation.

Related coverage: WiMAX Explained: Standards, Networks, and Broadband Choices

A change in wind speed or direction over a distance, horizontally or vertically. It describes a wind gradient; a microburst is a particular downdraft phenomenon that can produce hazardous wind shear.

Reference: National Weather Service: wind shear

10-gigabit small form-factor pluggable: a form factor for optical transceiver modules. The module's wavelength, reach and supported interface must match the equipment and fiber link.

Related coverage: XFP

Extensible Markup Language: a syntax for structured documents using named elements and attributes. Well-formed syntax and conformance to a particular schema are different checks.

Related coverage: XML Guides: Learning, Data, Publishing, and Community

An online library of explanatory guides, reference material and historical reporting across technology, science, arts and everyday subjects. Follow a topic guide for context beyond a short glossary definition.

Related coverage: Yenra library

The point on the sky directly above an observer. Its position is defined relative to the observer's location rather than a fixed star.

A legacy digital-telephony decoder specified to produce an analog output of 0 dBm for a digital milliwatt test signal. The term describes a reference-level test relationship rather than silence or a zero-voltage output.

Reference: ISED Canada: terminal-equipment glossary

Omitting nonsignificant zeros when displaying or representing a number. The formatting rules must preserve significant digits and any place-value information needed to interpret the value.