Glossary D - Yenra

37 definitions in this view. Search all 509 terms by name, phrase or topic.

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Audio & videoDAB

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.

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Audio & videoD-A (digital-to-analog)

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.

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Computers & specificationsDAS

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

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Security & privacyData sanitization

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)

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NetworksdBm

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)

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Historical names & systemsDCN

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.

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Computers & specificationsDDR

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)

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Security & privacyDe-identification

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

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PhotographyDepth of field

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

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Home & materialsDescaling

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

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NetworksDGPS

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.

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NetworksDHCP

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

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Security & privacyDifferential privacy

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

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Science & measurementDiffraction

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

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Security & privacyDigital certificate

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

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Rocks & EarthDigital elevation model

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

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Computers & specificationsDIMM

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.

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PhotographyDiopter adjustment

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

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Audio & videoDisc finalization

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)

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Audio & videoDisc image

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

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Rocks & EarthDiverging color scheme

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

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Security & privacyDKIM

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

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Security & privacyDMARC

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

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Audio & videoDMB

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.

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NetworksDNS

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)

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Science & measurementDoppler effect

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

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Science & measurementDPIV

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

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Audio & videoDRM

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.

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Science & measurementDS (dichotomous sampler)

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)

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Computers & specificationsDS (digital signal)

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

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Computers & specificationsDS (dual screen)

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

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Energy & environmentDSSC

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

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Transport & aerospaceDTC

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

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Tools & workshopDuty cycle

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

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Audio & videoDVD

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

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PhotographyDye-sublimation printing

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

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PhotographyDynamic range (imaging)

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

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A starting point for understanding

Each entry gives a concise meaning and, where useful, a distinction or practical example. Topic labels identify the context; the same acronym can have several meanings. Historical names remain useful when reading older coverage.

Follow the linked Yenra guides for fuller explanations and the reference links for supporting documentation. Health, technical and regulatory terms describe concepts; individual decisions depend on the applicable evidence, equipment and circumstances.

Collection updated October 13, 2026. Full glossary · AI Glossary