| CODE | ABBREVIATION |
| M | Mega- / Megabyte / Meter (usually as m) |
| M-) | See no evil |
| M/W | MicroWave |
| M2 | Mondo 2000 |
| M3P | Microsoft MultiMedia Productions |
| MA | bell / Maintenance Administrator / Milliampere (usually as mA) / Multiplexed Address |
| MAAP | Management And Administration Panels |
| MABO | Multiplier-Arithmetic Bolt-On |
| MAC | Macintosh Computer / Management and Administrative Computing / Media Access Control / Medium Access Control / Message Authentication / Multi Access Computers / Multiplexed Analog Components |
| MACBS | Multi-Access Cable Billing System |
| MACF | Multiple Association Control Function |
| MACH | Multi-layer ACtuator Head |
| MACINTOSH | Most Applications Crash; If Not The Operating System Hangs |
| MACL | Memory Access Control Logic |
| MACSTAR | Multiple Access Customer STAtion Rearrangement |
| MACU | Multidrop Auto Call Unit |
| MADN | Multiple Access Directory Numbers |
| MAGIK | Master Anarchists Giving Illicit Knowledge |
| MAH | Milliampere-Hour (usually as mAh) |
| MAI | Masters of Abstractions and Illusions |
| MAN | Metropolitan Area Network |
| MAP | Modular Arthemetic Processor / Manufacturing Automation Processor / Maintenance and Administration Position / Manufacturing Automation Protocol |
| MAPDU | Management Application Protocol Data Unit |
| MAPHIS | Memory Array and Processor for Human Intelligence Stor |
| MAPI | Messaging Application Programming Interface |
| MAPS | Multiservice Access PlatformS |
| MAPSS | Maintenance & Analysis Plan for Special Services |
| MAR | Microprogram Address Register |
| MARC | MAchine - Readable Cataloging / Market Analysis of Revenue and Customers System |
| MARCOM | Marketing Communications |
| MARS | Multicast Address Resolution Server/Service |
| MAS | MAin Store / Mass Announcement System |
| MASB | Mass Announcement System Bus |
| MASC | Mass Announcement System Controller |
| MASE | Message Administration Service Element |
| MASM | Mass Announcement System Memory |
| MASS | Mid-Atlantic and Southern States |
| MATAC | MATerial ACquisition |
| MATD | Maximum Acceptable Transit Delay |
| MATFAP | Metropolitan Area Transmission Facility Analysis Program |
| MATR | Minimum Average Time Requirement |
| MATV | Master Antenna Television |
| MAU | Medium Attachment Unit / Multistation Access Unit |
| MAW | Microsoft At Work |
| MB | Megabit (usually as - 1024 kilobytes) / MegaByte (usually as MB) / Memoryless Behavior / MotherBoard |
| MB/S | Megabits per Second (usually as mb/s) |
| MBBS | Major Bulletin Board System |
| MBG | Money Back Guarantee |
| MBIT | More (data) Bit |
| MBOD | Manufacturing Board of Directors |
| MBONE | Multicast backBONE |
| MBPS | Megabits Per Second (usually as Mbps) / MegaBytes Per |
| MBR | Master Boot Record |
| MBS | Master Boot Sector / Maximum Burst Size |
| MBT | Maximum Burst Tolerance |
| MBU | Manufacturing Business Unit |
| MBZS | Maximum Bandwidth Zero Suppression |
| MC | MicroChannel (architecture) / Mini Cartridge |
| MCA | Micro Channel Architecture |
| MCAD | Mechanical Computer Aided Design |
| MCAM | Manufacturing Corporate Account Manager |
| MCBTY(SN) | My Computer is Better than Yours (So Nyerrr) |
| MCC | Master Control Center / Microelectronics and Computer technology Corporation |
| MCCS | Mechanized Calling Card Service |
| MCE | Machine Check Exception |
| MCESS | Mechanical Component Engineering Support Service |
| MCF | MAC Convergence Function |
| MCGA | Multi-Color Graphics Array/Adaptor |
| MCH | Maintenance CHannel |
| MCHB | Maintenance CHannel Buffer |
| MCI | Media Control Interface / Microwave Communications Incorporated / |
| MCIAS | Multi-Channel Intelligent Announcement System |
| MCIS | Microsoft Commercial Internet System |
| MCN | Metropolitan Campus Network |
| MCO | Multiplexer Control Option |
| MCP | Master Control Program / Microsoft Certified Professional |
| MCR | Minimum Cell Rate |
| MCS | Maintenance Control Subsystem / Meeting Communications Service / Microsoft Consulting Services / Multinational Character Set |
| MCT | Manufacturing Cycle Time |
| MCTD | Mean Cell Transfer Delay |
| MCTRAP | Mechanized Customer Trouble Report Analysis Plan/Program |
| MCU | Mobile Control Unit / Multi Chip Unit / Multiport Conferencing Unit |
| MCVD | Modified Chemical Vapor Deposit |
| MD | Make Directory (DOS) / Management Domain / Mediation Device / Message Digest / Mobile Data / Multiple Dissemination / Medical Dumbo |
| MD5 | Message Digest 5 (algorithm) |
| MDA | Monochrome Display Adapter |
| MDACS | Modular Digital Access Control System |
| MDB | Microsoft DataBase (usually as .MDB) / Multidimensional DataBase |
| MDBS | Mobile DataBase System |
| MDC | Manipulation Detecting Code / Marker Distributor Control / Market Distributor Control / McAfee Development Center / Meridian Digital Centrex |
| MDCC | Mobile Data Capture & Communications |
| MDD | Marshals of Dynamic Discord |
| MDDB | MultiDimensional DataBase |
| MDDS | Media and Documentation Update Service |
| MDF | Main Distribution Frame |
| MDI | Medium Dependent Interface |
| MDI | Multiple Document Interface |
| MDIHMLAIGE | My dog is humping my leg and i'm getting excited |
| MDIS | Meta Data Interchange Specification |
| MD-IS | Mobile Data Intermediate System |
| MDK | Multimedia Development Kit |
| MDP | Modem Distribution Panel |
| MDR | Message Detail Record / Message Detail Recording |
| MDRAM | Multibank Dynamic Random Access Memory |
| MDS | Mail Delivery System / Message Design System(s) / Multiple Dataset System |
| MDSE | Message Delivery Service Element |
| MDSL | Medium-bit-rate Digital Subscriber Line |
| MDT | Mobile Data Terminal |
| MDTS | Modem Diagnostic and Test System |
| MDU | Marker Decoder Unit |
| MDX | Modular Digital eXchange |
| ME | Mapping Entity / Mechanical Engineering / Mutually Exclusive |
| MEC | Mobile Equipment Console |
| MEG | Megabyte |
| MELD | Mechanized Engineering and Layout for Distributing Frame |
| MEM | Manufacturing Engineering and Marketing |
| MEO | Medium Earth Orbit (satellite) |
| MERS | Most Economic Route Selection |
| MES | Manufacturing Execution System |
| MESI | Modified Exclusive Shared Invalid |
| MET | Memory Enhancement Technology (usually as MEt) / Multibutton Electronic Telephone |
| METI | Mailbase Exploring the Internet Workshop |
| MF | Mediation Function / Medium Frequency / Modulated Frequency / More Fragments / Multi-Frequency / Multiple Frequency |
| MFC | Microsoft Foundation Class(es) |
| MFENET | Magnetic Fusion Energy NETwork |
| MFG | More Friendly Garbage / Manufacturing |
| MFJ | Modification of Final Judgment / Modified Final Judgment |
| MFLOPS | Millions of FLoating point Operations Per Second |
| MFM | Modified Frequency Modulation / Most Favored Nation (trading status) |
| MFOTS | Military Fiber-Optic Transmission System |
| MFP | Microsoft Foundation Classes |
| MFP | MultiFunction Peripherals |
| MFPS | Mathematical Foundations of Programming Semantics |
| MFR | Multi-Frequency Receivers |
| MFS | Macintosh File System |
| MFT | Metallic Facility Terminal |
| MFTL | My Favourite Toy Language |
| MFTP | Multi-cast File Transfer Protocol |
| MG | MasterGroup |
| MGA | Monochrome Graphics Adapter |
| MGT | MasterGroup Translator |
| MH | Message Handling |
| MHBFY | My Heart Bleeds For You |
| MHD | Moving Head Disk |
| MHDC(A) | My Hard Drive Crashed (Again) |
| MHOTY | my hat's off to you |
| MHP | Message Handling Protocol |
| MHS | Message Handling Service / Message Handling System |
| MHTS | Message Handling Test System |
| MHZ | Megahertz (usually as MHz) |
| MI | Machine Interface / Mode Indicate / Multiple Inheritance |
| MIB | Man In Black super-secret government agents [X-Philes (fans)] / Management Information Base(s) |
| MIC | Management Information Center / Management Integration Consortium / Medium Interface Cable / Medium Interface Connector / Memory In Cassette / Microphone / Microsoft Internet Chat / Mode Indicate - Common |
| MICA | Modem ISDN Channel Aggregation |
| MICE | Modular Integrated Communications Environment |
| MICR | Magnetic Ink Character Recognition |
| MICROSOFT | Majority In Country Realise Operating System Of Fools & Techheads / Making Imaginative Creations Requires Other Superior Forms Of Faster Technology / Most Idiots Can't Realize: Obsolete Software Organization For Technology / Most Intelligent Customers Real |
| MICROTEL | Microsoft-Intel |
| MICS | Management Information Conformance Statement |
| MID | Message ID / Message Identifier |
| MIDA | Message Interchange for Distributed Application |
| MIDAS | Manchester Information Datasets and Associated Services / Master Integrated Distribution Subcontracting Agreement |
| MIDI | Musical Instrument Digital Interface |
| MIDR | Mosaicked Image Data Record |
| MIF | Management Information File / Master Item File |
| MIFF | Management Information Format File |
| MIG | Metal-In-Gap |
| MII | Medium Independent Interface |
| MIL | Management Information Library |
| MILES | Merisel's Information and Logistical Efficency System |
| MILNET | Military Network |
| MIM | Management Information Model |
| MIME | Multimedia/Multipurpose Internet Mail Extension(s) |
| MIMG | Media Industry Marketing Group |
| MIN | Mobile Identification Number |
| MIND | Modular Interactive Network Designer |
| MINX | Multimedia Information Network Exchange |
| MIO | Modular Input/Output |
| MIP | Multim In Parvum |
| MIPL | Multimission Image Processing Laboratory/Library |
| MIPS | Meaningless Indication of Processor Speed / Millions of Instructions Per Second / Multimission Image Processing Subsystem |
| MIR | Material Increase Request / Maximum Information Rate / Micro-Instruction Register |
| mIRC | (is defined as) Magnificent Internet Relay Chat (according to `rock in #Undernet) |
| MIS | Management Information System(s) |
| MISCF | MISCellaneous Frame |
| MISG | Market Information Services Group |
| MIT | Management Information Tree / Massachusetts Institute of Technology / Master Installation Tape |
| MITI | Ministry of International Trade and Industry |
| MITS | Microcomputer Interactive Test System |
| MITV | Microsoft Interactive Television |
| MJU | Multipoint Junction Unit |
| MKDIR | Make Directory (DOS) |
| MLA | Multiple Letter Acronym |
| MLC | MiniLine Card |
| MLCD | Multi-Line Call Detail |
| MLDS | Medium Large Disk Systems |
| MLHG | MultiLine Hunt Group |
| MLI | Multiple Link Interface |
| MLID | Multiple Link Interface Driver |
| MLN | Main Listed Number |
| MLP | Maynard List Price / MultiLink Procedures / MultiLink Protocol |
| MLPC | Model Level planning Committee |
| MLPP | MultiLevel Precedence and Preemption |
| MLPPP | MultiLink Point to Point Protocol |
| MLR | Multichannel Linear Recording |
| MLS | Multi-Level Security |
| MLT | Mechanized Loop Testing / Multiple Logical Terminals |
| MM | Millimeter (usually as mm) / Multimedia |
| MMAC | MultiMedia Access Center |
| MMC | Mickey Mouse Club / Minicomputer Maintenance Center / Multimedia Marketing Council |
| MMCD | MultiMedia Compact Disc (format) |
| MMD | MultiMedia Document |
| MMDF | Multi-channel Memorandum Distribution Facility |
| MMDS | Multipoint Multichannel Distribution Service |
| MMF | MultiMode Fiber / MultiMode Fiberoptic (cable) |
| MMFS | Manufacturing Message Format Standard |
| MMGT | Multimaster Group Translator |
| MMHS | Military Message Handling System |
| MMI | Man Machine Interface |
| MMIF | My Mouth Is Full |
| MMJ | Modified Modular Jack |
| MML | Man - Machine Language |
| MMOC | Minicomputer Maintenance Operations Center |
| MMS | Main Memory Status / Manufacturing Message Service/Standard / Manufacturing Messaging Specification / Memory Management System / Modular Measurement System |
| MMT | Multimedia Multiparty Teleconferencing |
| MMU | Memory Management Unit |
| MMX | Mastergroup Multiplex(er) / Multimedia Extension(s) |
| MNCS | Multipoint Network Control System |
| MNDS | Multi-Network Design System |
| MNP | Microcom Networking Protocol |
| MO | Magneto-Optical / Managed Object |
| MOAC | Message Origin Authentication Check |
| MOAT | Mother Of All Tests |
| MOB | Men Of Business |
| MOC | Manufacturing Outreach Center |
| MOCA | Merisel Open Computing Alliance |
| MOCS | Managed-Object Conformance Statement |
| MOD | Masters Of Deception/Destruction/Disaster |
| MODEM | MOdulator-DEModulator |
| MOF | Master Order Form |
| MOG | Minicomputer Operations Group |
| MOL | Microsoft Open License |
| MOLAP | Multidimensional OnLine Analytical Processing |
| MOLI | Microsoft OnLine Institute |
| MOM | Manager-Of-Manager / Message Oriented Middleware / Microsoft Office Manager |
| MOMPL | one MOMent PLease... |
| MOMV | Manned Orbital Maneuvering Vehicle |
| MOO | MUD Object Oriented / Multi-user dungeon Object-Oriented |
| MOP | Maintenance Operations Protocol |
| MORF | Male OR Female (usually as MorF) |
| MOS | Material Order System / Metal Oxide Semiconductor |
| MOSFET | Metal Oxide Semiconductor Field Effect Transistor |
| MOSIS | Metal Oxide Semiconductor Implementation System |
| MOSPF | Multicast Open Shortest Path First |
| MOSS | MIME Object Security Services |
| MOST | Metal Oxide Semiconductor Transistor |
| MOT | Managed Object to Test / Masters Of Technology / Means Of Testing |
| MOTAS | Member Of The Appropriate Sex |
| MOTD | Message of the day |
| MOTIS | Message Oriented Text Interchange System |
| MOTOS | Member Of The Opposite Sex |
| MOTSS | Member Of The Same Sex |
| MoU | Memorandum of Understanding |
| MOV | Metal Oxide Varistor |
| MP | Machine Processable / Managing Process / Modem Port / Multilink Protocol / Multi-Processor |
| MPC | Mathematics of Program Construction / Multimedia Personal Computer |
| MPCC | MultiProtocol Communications Controller |
| MPCH | Main Parallel CHannel |
| MPD | Mini Port Driver |
| MPDT | Multi-Peer Data Transmission |
| MPDU | Message Protocol Data Unit |
| MPE | MultiProgramming Executive |
| MPEG | Motion Picture Expert's Group |
| MPF | Multilink Packet Fragmentation |
| MPI | Message Passing Interface / Multiple Protocol Interface |
| MPL | Multi-schedule Private Line |
| MPLS | Multi-Protocol Label Switching |
| MPME | Manufacturing Process and Material Engineering |
| MPOA | Multiple Protocol Over ATM / MultiProtocol Over ATM |
| MPOW | Multiple Purpose Operator Workstation |
| MPP | Massively Parallel Processor(ing) / Multilink Point-to-point Protocol |
| MPPD | Multi-Purpose Peripheral Device |
| MPR | Multiple Provider Router / Multi-Port Repeater / Multi-Protocol Router |
| MPS | Master Production Schedule / Multi-Processor Specification |
| MPSA | MultiProcessor Server Architecture |
| MPSC | Manufacturing Planning and Control Systems |
| MPT | Ministry of Posts and Telecommunications |
| MPTM | Multi-Parity Test Method |
| MPW | Macintosh Programmers' Workshop |
| MPX | MultiPleXer |
| MQ | Message Queing |
| MQI | Message Queuing Interface |
| MR | (modem) Modem Ready / Magneto-Resistive / Message Retrieval |
| MRAA | Meter Reading Access Arrangement |
| MRAM | Multibank Random Access Memory |
| MRB | Multiple Resolution Bitmaps (usually as .MRB) |
| MRC | Management Response Center / Manufacturing Resource Center / Market Research Center / Medical Research Council |
| MRCS | Multi-Rate Circuit Switching |
| MRF | Maintenance Reset Function |
| MRI | Magnetic Resonance Imaging |
| MRM | Maximum Rights Mask / Most Recently used Master |
| MRO | Multi-Region Operation |
| MRP | Manufacturing Resource Planning |
| MRSE | Message Retrieval Service Element |
| MRX | Magneto-Resistive eXtended |
| MS | Maintenance State / Message Store / Meta Signaling / Microsoft / Microsoft System(s) / Milli-seconds (usually as ms) / More Segments |
| MSAP | MAC Service Access Point |
| MSAT | Mobile SATellite |
| MSAU | Multi-Station Access Unit |
| MSB | Mid-Range Systems Business / Most Significant Bit / Most Significant Byte |
| MSC | Media Stimulated Calling |
| MSCDEX | Microsoft Compact Disc Extensions |
| MSCP | Mass Storage Control Protocol |
| MSD | Micro Systems Development / Microsoft Diagnotic / Microwave Semiconductor Device / Most Significant Digit |
| MSDL | Microsoft Download (service) |
| MSDN | Microsoft Developer Network |
| MSDOS | MicroSoft Disk Operating System |
| MS-DOS | Microsoft Disk Operating System |
| MSDS | Material Safety Data Sheet |
| MSF | Measurement Summarization Function |
| MSFC | Marshall Space Flight Center |
| MSG | Message |
| MSI | Medium Scale Integration / Mustang Software Inc. |
| MSJ | Microsoft Systems Journal |
| MSL | Microsoft Library / Mirrored-Server Link |
| MSM | Matrix Switch Module |
| MSN | Microsoft Network / Monitoring cell Sequence Number / Multiple Subscriber Number |
| MSO | Mobile Switching Office / Multiple System(s) Operator(s) |
| MSP | Message Security Protocol |
| MSPM | Manufacturing System Program Manager |
| MSR | Model-Specific Registers |
| MSRP | Manufacturer's Suggested Retail Price |
| MSS | Maritime Satellite Service / Metropolitan Switching System / Mobile Satellite Service / Modem Substitution Switch / Multiprotocol Switched Services |
| MSSC | Marketing Sales Strategy Committee |
| MSSE | Message Submission Service Element |
| MSSSE | Message Submission and Storage Service Element |
| MST | Minimum Spanning Tree |
| MSTP | Multimission Software Transmission Project |
| MSTS | MicroSoft Terminal Server |
| MSU | Message Signal Unit / Microsoft University / Modem Sharing Unit |
| MSVC | Meta-Signaling Virtual Channel |
| MT | Measured Time / Mitel |
| MTA | Mail Transfer / Mail Transfer Agent / Major Trading Area / Message Transfer Agent |
| MTAE | Message Transfer Agent Entity |
| MTAU | Metallic Test Access Unit |
| MTB | Magnetic Tape Billing |
| MTBF | Mean Time Before Failure / Mean Time Between Failure(s) |
| MTBSI | Mean Time Between System Interruptions |
| MTC | Manufacturing Technology Center |
| MTCN | Minimum Throughput Class Negotiation |
| MTEBBS | Maryland Technology Education Bulletin Board Service |
| MTF | Master Test Frame / More To Follow |
| MTFBWY | May The Force Be With You |
| MTL | Message Transfer Layer |
| MTOS | MultiTasking Operating System |
| MTP | Message Transfer Part (SS7) / Message Transfer Protocol |
| MTR | Mechanized Time Reporting |
| MTS | Message Telecommunications Service / Message Telephone / Message Transfer Service / Message Transfer System / Message Transport Service / Microsoft Transaction Server / Mobile Telephone Service |
| MTSE | Message Transfer Service Element |
| MTSL | Message Transfer SubLayer |
| MTSO | Mobile Telephone Switching Office |
| MTTA | Multi-Tenant Telecommunications Association |
| MTTR | Mean Time To Repair |
| MTU | Maintenance Termination Unit / Maximum Transmission Unit / Media Tech Unit / Message Transfer Unit |
| MTX | Mobile Telephone Exchange |
| MU | Message Unit |
| MUA | Mail User Agent |
| MUAA | Modem User's Association of America |
| MUD | Multi/Multiple User Dungeon / Multi-User Dimension (games) / Multi-User Dimensions / Multi-User Domain |
| MUF | Maximum Usable Frequency |
| MUG | Multi User Game |
| MULDEM | Multiplexer/Demultiplexer |
| MULTICS | Multiplexed Information and Computing Service |
| MUP | Multiple Uniform naming convention Provider |
| MUS | MultiUser System |
| MUSH | Multi-User Shared Hallucination |
| MUX | Multiplexer |
| MV | Millivolt (usually as mV) |
| MVB | MicroVax Business |
| MVID | Major Vector ID |
| MVIP | Multi-Vendor Integration Protocol |
| MVP | Modular Voice Processor / Multiline Variety Package |
| MVS | Multiple Virtual Storage |
| MVS/ESA | Multiple Virtual Storage / Enterprise Systems Architecture |
| MVS/SP | Multiple Virtual Storage / System Product |
| MVS/TSO | Multiple Virtual Storage/Time Sharing Option |
| MVS/XA | Multiple Virtual Storage / eXtended Architecture |
| MW | MicroWave / MilliWatt (usually as mW) / MultiWink |
| MWI | Message Waiting Indicator |
| MWN | Message Waiting Notification |
| MX | Mail Exchange (record) / Mail Exchanger |
| MXU | MultipleXer Unit |
| MYOB | Mind Your Own Business |
M
MA :- Master of Arts
MAIT :- Manufacturer's Association of Information Technology
MAPP :- Madras Atomic Power Project
MASER :- Microwave Amplification by Stimulated Emission of Radiation
MBA :- Master of Business Administration
MBBS :- Bachelor of Medicine and Bachelor of Surgery
MCA :- Master of Computer Application
MCC :- Melbourne Cricket Club
MCF :- Master Control Facility
MCOCA :- Maharashtra Control of Organized Crime Act
MD :- Doctor of Medicine
MECL :- Mineral Exploration Corporation Limited
MEET :- Mission for Extension of Educational Technology
MENAS :- Middle East Navigation Aids Service
MERC :- Maharashtra Electricity Regulatory Commission
METO :- Middle East Treaty Organization
MFALA :- Marginal Farmers and Agricultural Labour Agency
MFALS :- Marginal Farmers and Agricultural Liberation Scheme
MFN :- Most Favoured Nation
MI :- Military Intelligence
MIGA :- Multilateral Investment Guarantee Agency
MISA :- Maintenance of Internal Security Act
MIT :- Massachusetts Institute of Technology
MLA :- Member of Legislative Assembly
MLC :- Member of Legislative Council
MMDS :- Multiple Microwave Distribution System
MMTC :- Minerals and Metals Trading Corporation
MNAMS :- Member of National Academy of Medical Sciences
MNC :- Multi National Corporation
MNLF :- Moro National Liberation Front
MPLS :- Micro Protocol Label Switching
MPLANDS :- Member of the Parliament Local Areas Development Scheme
MRTPC :- Monopoly and Restrictive Trade Practice Commission
MRTS :- Mass Rapid Transport System
MSA :- Maritime Safety Agency
MST :- Multi System Transmission
MTCT :- Mother to Child Transmission
MTCR :- Missile Technology Control Regime
MODVAT :- Modified Value Added Tax
MULTA :- Muslim United Liberation Tigers of Assam
