Glossary M - Yenra

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

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Computers & specificationsM.2

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

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NetworksM2M

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.

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Security & privacyMalware

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

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Rocks & EarthMap projection

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

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Rocks & EarthMap 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

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Science & measurementMass spectrometry

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

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Science & measurementMass-to-charge ratio

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

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Computers & specificationsMb (megabit)

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

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Computers & specificationsMB (megabyte)

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

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Computers & specificationsMbps

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

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Computers & specificationsMB/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

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Audio & videoMDTV

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

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Science & measurementMeasurement resolution

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

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PhotographyMegapixel

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

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Web & documentsMetadata

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

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Rocks & EarthMetamorphic rock

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

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Computers & specificationsMilliampere-hour

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

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Web & documentsMIME

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)

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Rocks & EarthMineral

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

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Tools & workshopMiter cut

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)

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Transport & aerospaceMLRS

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.

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Historical names & systemsMMH

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

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Historical names & systemsMMS (former U.S. agency)

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.

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NetworksMMS (messaging)

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

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NetworksMNO

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

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Security & privacyMobile device management

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

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NetworksMPLS

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

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Health & careMRI

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.

Reference: NIBIB: magnetic resonance imaging

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Historical names & systemsMTNS

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

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Computers & specificationsMT/s

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)

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NetworksMTU

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)

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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