List of acronyms and initialisms: M

(Main list of acronyms and initialisms)

• m - (s) Metre - Milli
• M - (s) Mega - One Thousand (in Roman numerals)

MA

• mA - (s) Milliampere
• Ma - (s) Megaannum
• MA - (s) Madagascar (FIPS 10-4 country code) - (i) Marijuana Anonymous - (i) Master of Arts - Massachusetts (postal symbol) - Megaampere - Morocco (ISO 3166 digram)
• MAA - (i) Mathematical Association of America
• MAAMAW - (i) Modelling Autonomous Agents in a Multi-Agent World
• MAC - (s) Macau (ISO 3166 trigram) - (a) U.S. Military Airlift Command (1966-1992)
• MACA - (i) Military Aid to the Civil Authorities
• MACE - (a) Multi-Agent Computing Environment
• MACHO - (p) MAssive Compact Halo Object
• MAD - (a) Magnetic Anomaly Detector - (s) Moroccan dirham (ISO 4217 currency code) - (a) Mutual Assured Destruction
• MADD - (a) Mothers Against Drunk Driving - MyoAdenylate Deaminase Deficiency - (p) Multiply-Add
• MAF - (i) Maintenance Action Form
• MAGIC - (a) Major Atmospheric Gamma-ray Imaging Cherenkov (telescope)
• MAGNETAR - (p) Metaprogrammable AGent NETwork ARchitecture
• MAGTF - (i) Marine Air-Ground Task Force
• mah - (s) Marshallese language (ISO 639-2 code)
• mal - (s) Malayalam language (ISO 639-2 code)
• MALD - (a) Miniature Air-Launched Decoy
• MANPADS - (p) MAN-Portable Air Defence System
• MANPRINT - (p) MANpower and PeRsonnel INTegration
• MAO - (i/a) Molėtų astronomijos observatorija (Moletai Astronomical Observatory) - MonoAmine Oxidase
• MAPS - (a) Monitoring Avian Productivity and Survivorship
• MAQS - (a) Museum of the American Quilter's Society ("max")
• mar - (s) Marathi language (ISO 639-2 code)
• MAR - (s) Morocco (ISO 3166 trigram)
• MarBEF - (p) Marine Biodiversity and Ecosystem Functioning
• MARC - (a) MAchine Readable Cataloging (often also defined as MAchine Readable Code)
• MARCENT - (p) United States Marine Forces Central Command
• MARFORCC - (p) Marine Force Component Commander
• MAS - (i) NATO Military Agency for Standardisation
• MASAS - (a) Monte Agliale Supernovae and Asteroid Survey
• Maser - (a) Microwave Amplification by Stimulated Emission of Radiation
• MASH - (a) Mobile Army Surgical Hospital
• MASINT - (p) Measurement And Signature Intelligence
• MATREX - (p) Modeling Architecture for Technology, Research & EXperimentation
• MATS - (a) U.S. Military Air Transport Service (1948-1966)
• MAVS - (a/i) Mobile Artillery Vehicle System
• MAX - (i) Meta-reasoning Architecture for "X"

MB

• MB - (s) Manitoba (postal symbol) - Martinique (FIPS 10-4 territory code)
• MBA - (i) Main Battle Area - Main Belt Asteroid - Masters of Business Administration
• MBBL - (i) (U.S. Armor Center) Mounted Battlespace Battle Laboratory
• MBCC - (i) Migratory Bird Conservation Commission (U.S.)
• MBCS - (i) Multi-Byte Character Set
• MBE - (p) Member of the Order of the British Empire
• MBIDST - (i) Member of the British Institute of Dental and Surgical Technologists
• MBM - (i) Meat and Bone Meal
• MBT - (i) Main Battle Tank
• MBTA - (i) Massachusetts Bay Transportation Authority - Migratory Bird Treaty Act (U.S.)
• MBTI - (i) Myers-Briggs Type Indicator

MC

• mC - (s) Millicoulomb
• MC - (s) Macau (FIPS 10-4 territory code) - (i) Master of Ceremonies - (s) Megacoulomb - (i) Military Cross (bravery award) - (s) Monaco (ISO 3166 digram) - (i) Mortar Carrier - (s) Eleven Hundred (in Roman numerals)
• MCA - (i) Micro Channel Architecture - MultiChannel Analyzer - Master of Computer Applications
• MCC - (i) Marylebone Cricket Club - Mission Control Centre - Movement Control Centre
• MCD - (i) Minimal Cerebral Dysfunction
• MCDL - (i) Model Composition Definition Language
• MC&G - (i) Mapping, Charting, and Geodesy
• MCI - (i) Microwave Communications, Inc.
• MCIS - (i) Mellon Collie and the Infinite Sadness
• MCM - (i) Mine Counter-Measures
• MCMV - (i) Mine Counter-Measure Vessel
• MCO - (s) Monaco (ISO 3166 trigram) - (i) Movement Control Officer - (i) Major Combat Operation
• MCP - (i) Maintenance Collection Point - Male Chauvinist Pig
• MCSF - (i) Marine Corps Security Forces
• MCT - (i) Movement Control Team
• MCTIS - (i) Mounted Co-operative Target Identification System
• MCR - (i) My Chemical Romance

MD

• Md - (s) Mendelevium
• MD - (s) Fifteen Hundred (in Roman numerals) - Maryland (postal symbol) - (i) Medicinae Doctor (Doctor of Medicine/Medical Doctor) - Mentioned in Dispatches (military) - (s) Moldova (FIPS 10-4 country code; ISO 3166 digram)
• MDA - (i) Main Defensive Action/Area - (s) Moldova (ISO 3166 trigram) - Muscular Dystrophy Association
• MDF - (i) Main distribution frame - Medium-Density Fibreboard
• MDG - (s) Madagascar (ISO 3166 trigram) - (i) UN Millennium Development Goal
• MDL - (s) Moldovan leu (ISO 4217 currency code)
• MDM - (i) Michigan Dartmouth MIT telescope consortium
• MDMA - (i) MethyleneDioxy-MethylAmphetamine (also known as "Ecstasy")
• MDO - (i) Membership Driven Organisation
• MDP - (i) Markov Decision Process
• MDT - (i) Mountain Daylight Saving Time (UTC-6 hours)
• MDV - (s) Maldives (ISO 3166 trigram)
• MDW - (i) Chicago Midway International Airport in Chicago, Illinois (IATA Airport Code MDW) - Military District of Washington - Minnesota, Dakota and Western Railroad (AAR reporting mark MDW)

ME

• Me - (s) Messerschmitt
• ME - (s) Maine (postal symbol) - (i) Mechanical Engineer[ing] - Medical Examiner - Middle East - (s) Middle East Airlines (IATA code) - (i) Memory Effect - Myalgic Encephalomyelitis
• MEA - (i) Maine Educational Assessment - Middle East Airlines - Millennium Ecosystem Assessment - Minimum Enroute Altitude - Mono-ethanol Amine - Multilateral Environmental Agreement
• MEC - (s) Maine Central Railroad (AAR reporting mark) - Manta, Ecuador (IATA location identifier) - (i) Model European Council - Mountain Equipment Co-op
• MECC - (a) Minnesota Educational Computing Consortium (later Corporation, dissolved 1999)
• MECO - (a) Main Engine Cutoff (NASA code for point in Space Shuttle assent when three main engines are shut down prior to External Tank (ET) separation)
• MEDEVAC - (p) Medical Evacuation
• MEDS - (a) Mission Essential Data Set
• MEF - (i) U.S. Marine Expeditionary Force - Minimum Essential Facility - Mission Essential Force
• MEG - (i) MagnetoEncephaloGraphy
• MEI - (i) Matsushita Electric Industrial Co., Ltd.
• MEK - (i) Magyar Elektronikus Konyvtar - Message Encryption Key - Methyl ethyl ketone - (p) Mujahideen al-Khalq
• MEL - (i) Maya Embedded Language - Michigan Electronic Library
• MEM - (i) Message Exchange Mechanism - (p) Microelectromechanical
• MEMS - (p) Microelectromechanical System
• MEO - (a) Medium Earth Orbit - Most Efficient Organization
• MEP - (i) Mechanical Electrical Plumbing - Member of the European Parliament - Missions étrangères de Paris (French for "Paris Foreign Missions") - Model European Parliament
• MER - (i) Mars Exploration Rover
• MERL - (i) Mitsubishi Electric Research Laboratories
• MES - (i) Marconi Electronic Systems - Medium Edison Screw
• MESSENGER – (p) MErcury Surface, Space ENvironment, GEochemistry and Ranging
• MET - (p) Meteorological - (a) Middle European Time
• METAR - (p) [Meteorological] Aviation Routine weather report
• METL - (i/a) Mission Essential Task List ("mettle")
• METOC - (p) Meteorological and Oceanographic
• METT-T - (a/i) Mission, Enemy, Terrain, Troops, and Time available (mnemonic)
• METT-TC - (a/i) Mission, Enemy, Terrain [and weather], Troops [and support], Time [available] and Civilian considerations (mnemonic)
• MEU - (i) U.S. Marine Expeditionary Unit - Maximum Expected Utility
• MeV - (s) Megaelectronvolt
• MEV - (i) Medical Evacuation Vehicle - Musica Elettronica Viva
• MEX - (s) Mexico (ISO 3166 trigram)
• MEZ - (i) Missile Engagement Zone
• MES - (a) Manufacturing Execution Systems

MF

• mF - (s) Millifarad
• MF - (s) Mayotte (FIPS 10-4 territory code) - Megafarad

MG

• mg - (s) Malagasy language (ISO 639-1 code) - Milligram
• Mg - (s) Magnesium - Megagram
• MG - (i) Machine Gun - (s) Madagascar (ISO 3166 digram) - (s) Major General - (s) Mongolia (FIPS 10-4 country code) - (i) Morris Garage
• MGA - (s) Malagasy ariary (ISO 4217 currency code)
• MGB - (i) Medium Girder Bridge, Motor Gun Boat
• MGM - (i) Metro Goldwyn Mayer - (s) Montgomery, AL (Airport Code)
• MGPAM - My Gym Partner's a Monkey
• MGS - (i) Mobile Gun System

MH

• mh - (s) Marshallese language (ISO 639-1 code)
• mH - (s) Millihenry
• MH - (s) Marshall Islands (postal symbol; ISO 3166 digram) - Megahenry - Montserrat (FIPS 10-4 territory code)
• MHC - (i) Major Histocompatibility Complex
• MHHW - (i) Mean Higher High Water (nautical charts)
• MHL - (s) Marshall Islands (ISO 3166 trigram)
• MHLW - (i) Mean Higher Low Water (nautical charts)
• MHRA - (i) (UK) Medicines and Healthcare products Regulatory Agency
• MHW - (i) Mean High Water (nautical charts)
• MHWN - (i) Mean High Water Neaps (nautical charts)
• MHWS - (i) Mean High Water Springs (nautical charts)
• MHz - (s) Megahertz

MI

• mi - (s) Māori language (ISO 639-1 code)
• Mi - (s) Mebi
• MI - (s) Malawi (FIPS 10-4 country code) - Michigan (postal symbol) - Midway Islands (ISO 3166 digram; obsolete 1986) - (i) Military Intelligence
• MIA - (i) Missing In Action
• MIB - (i) Men In Black - Mint In Box (Internet auction/trading listings)
• MICLIC - (p) Mine Clearing Line Charge
• MICOM - (p) Missile Command
• MICV - (i) Mechanised Infantry Combat Vehicle
• MID - (s) Midway Islands (ISO 3166 trigram; obsolete 1986)
• MIDI - (a) Musical Instrument Digital Interface
• MIDAS - (a) Man-machine Integration Design and Analysis System
• MIDS - (i) Multi-Function Information Distribution System
• MIFG - (s) Shallow Fog (METAR Code)
• MIKE - (a) Monitoring of Illegal Killing of Elephants
• MIL - (i) Man-In-the-Loop
• MIL-AASPEM - (i) Man-In-the-Loop AASPEM
• MILAN - (p) Missile d´infanterie léger antichar (French, "Anti-Tank Light Infantry Missile")
• MILES - (a) Multiple Integrated Laser Engagement System (live combat simulation)
• MILF - (i) Moro Islamic Liberation Front - (a) Mother I'd Like To Fuck
• MILSATCOM - (p) Military Satellite Communications
• MILSET - (a) Mouvement International pour le Loisir Scientifique Et Technique (French, "International Movement for Leisure Activities in Science and Technology")
• MILSTRIP - (p) Military Standard Requisitioning and Issue Procedure
• MIMAROPA - (p) Mindoro, Marinduque, Romblon, Palawan (a region in the Philippines)
• MIMOSA - (a) MIcroMeasurements Of Satellite Acceleration
• MIMPT - (i) Member of the Institute of Maxillofacial Prosthetists and Technologists
• MIP - (a) Multilateral Interoperability Programme - Multiple Identity Poster
• MIRA - (a) MILAN Infra-Red Acquisition (thermal sight)
• MIRV - (a) Multiple Independent Reentry Vehicle
• MIS - (a) Management Information Systems - Museum Information System
• MISREP - (p) Mission Report
• MISSI - (a) Multilevel Information System Security Initiative
• MIT - (i) Massachusetts Institute of Technology - methylisothiazoline - Milli Istihbarad Teskilati (Intelligence service of Turkey)
• MITL - (i) Man-In-The-Loop
• MITS - see entry

MJ

• mJ - (s) Millijoule
• MJ - (s) Megajoule
• MJD - (i) Modified Julian Day
• MJP - (i) Military Judgement Panel

MK

• mk - (s) Macedonian language (ISO 639-1 code)
• mK - (s) Millikelvin
• MK - (s) Air Mauritius (IATA code) - Macedonia (ISO 3166 digram; FIPS 10-4 country code) - (i) Mandalskameratene (Norwegian football club) - (s) Megakelvin - (i) Missionary Kids - Mortal Kombat (game)
• mkd - (s) Macedonian language (ISO 639-2 code)
• MKD - (s) Macedonian denar (ISO 4217 currency code) - Republic of Macedonia (ISO 3166 trigram)
• MKO - (i) Mojahedin-e-Khalq Organization (Arabic "People's Mujahedin of Iran")
• MKS - (i) Metre-Kilogram-Second (system of units) - (p) MKS Inc. software company
• MKSA - (i) Metre-Kilogram-Second-Ampere (system of units)
• MKT - (i) Missouri-Kansas-Texas Railroad (1865-1989) - Mortal Kombat Trilogy

ML

• ml - (s) Malayalam language (ISO 639-1 code)
• mL - (s) Millilitre
• ML - (s) Mali (FIPS 10-4 country code; ISO 3166 digram) - (i) Maximum Likelihood - (s) Megalitre
• MLA - (i) Martial Law Administration of Bangladesh - Master of Landscape Architecture - Medical Library Association - Member of Legislative Assembly - Modern Language Association - Mutual Legal Assistance treaty - Myelosis Leucemica Acuta
• MLB - (i) Major League Baseball
• MLC - (i) Member of the Legislative Council (in India)
• MLE - (i) Maximum likelihood estimation
• mlg - (s) Malagasy language (ISO 639-2 code)
• MLHW - (i) Mean Lower High Water (nautical charts)
• MLI - (s) Mali (ISO 3166 trigram)
• MLK - (i) Martin Luther King, Jr.
• MLL - (i) Major League Lacrosse
• MLLW - (i) Mean Lower Low Water (nautical charts)
• MLRS - (i) Multiple-Launch Rocket System
• MLS - (i) Major League Soccer - (i) Multiple Listing Service
• MLSR - (i) Missing, Lost or Stolen Report
• mlt - (s) Maltese language (ISO 639-2 code)
• MLT - (s) Malta (ISO 3166 trigram)
• MLVW - (i) Medium Logistics Vehicle, Wheeled
• MLW - (i) Mean Low Water (nautical charts)
• MLWN - (i) Mean Low Water Neaps (nautical charts)
• MLWS - (i) Mean Low Water Springs (nautical charts)

MM

• mm - (s) Millimetre
• Mm - (s) Megametre
• MM - (i) Military Medal - (s) Myanmar (ISO 3166 digram) - Two Thousand (in Roman numerals)
• MMA - (i) Moving Mechanical Assembly
• MMC - (p) Machinist's Mate, Chief (USN rating) - (i) Materiel Management Centre
• MMCM - (p) Machinist's Mate, Master Chief (USN rating) - (i) Magnetic Mine Counter Measure
• MMCS - (p) Machinist's Mate, Senior Chief (USN rating)
• MMEV - (i) Multi-Mission Effects Vehicle
• MMI - (i) Man-Machine Interface
• MMI - (i) Magical MonkeyZ Inc.
• MMK - (s) Burmese kyat (ISO 4217 currency code)
• MMO - (i) Massively Multiplayer Online (computer game)
• MMOR - (i) Master of Management in Operations Research
• MMPR - Mighty Morphin Power Rangers
• MMR - (i) Measles, Mumps and Rubella vaccine - (s) Myanmar (ISO 3166 trigram)
• MMS - (i) Multimission Modular Spacecraft
• MMU - (i) Manchester Metropolitan University - (i) Manned Manoeuvring Unit
• MMW - (p) Millimetre Wave (radar, from "mm Wave")

MN

• mn - (s) Mongolian language (ISO 639-1 code)
• mN - (s) Millinewton
• Mn - (s) Manganese
• MN - (s) Meganewton - Minnesota (postal symbol) - Monaco (FIPS 10-4 country code) - Mongolia (ISO 3166 digram)
• MNB - (p) Multinational Brigade
• MNB C - (p) Multinational Brigade Centre (KFOR)
• MND - (i) Motor Neurone Disease - (p) Multinational Division
• MNG - (i) Multiple-image Network Graphics - (s) Mongolia (ISO 3166 trigram)
• MNMF - (i) Multi-National Maritime Force
• MNP - (s) Northern Mariana Islands (ISO 3166 trigram)
• MNS - (i) Mission Needs Statement
• MNT - (p) Molecular nanotechnology - (s) Mongolian tugrik (ISO 4217 currency code)

MO

• mo - (s) Moldovan language (ISO 639-1 code)
• Mo - (s) Molybdenum
• MO - (s) Macau (ISO 3166 digram) - (i) Medical Officer - (s) Missouri (postal symbol) - (i) modus operandi (Latin, "mode of operation") - (s) Morocco (FIPS 10-4 country code)
• MOA - Museum of Art (Brigham Young University)
• MOAB - (a) Massive Ordnance Air Blast (official) - Mother Of All Bombs (slang)
• MOB - (i) Man Over Board - Marching Owl Band - Movable Object Block
• MOC - (i) Macedonian Orthodox Church - Measure Of Capability - Mission Operations Centre - My Own Creation (Lego)
• MOCAS - (a) Mechanization Of Contract Administration Services
• MoD - (i) Ministry of Defence (United Kingdom) and various other countries
• MOD - (i) Magneto-optical disc - Masters of Deception - Minimum Object Distance - Multiple Organ Dysfunction
• MoDAF - (p) Ministry of Defence Architecture Framework ("moh-daff")
• modem - (p) Modulator-Demodulator
• ModSAF - (p) Modular Semi-Automated Forces (military simulation)
• Moe - (a) Marvel of entertainment
• MOE - (i) Measure Of Effectiveness
• MOF - (a/i) Ministry of Finance (Japan)
• MOFA - (a/i) Ministry of Foreign Affairs (Japan)
• MOH - (a/i) Medal of Honor - Music On Hold
• MOID - (i) Minimum Orbital Intersection Distance
• mol - (s) Moldovan language (ISO 639-2 code) - mole (unit)
• MOLO - (a) Mobile Other Licenced Operator (UK)
• MoM - (a) Multiple of the median
• MOM - (a) Management Object Model (HLA) - Message Oriented Middleware
• MoMA - (a) Museum of Modern Art (NYC)
• mon - (s) Mongolian language (ISO 639-2 code)
• MOND - (p) Modified Newtonian Dynamics
• MOO - (i) Measure Of Outcome
• MOOTW - (p) Military Operations Other Than War ("moot-double-you")
• MOP - (s) Macau pataca (ISO 4217 currency code) - (i) Measure Of Performance
• MOPE - (a) Ministry of Population and Environment (Nepal) - Most Oppressed People Ever (politics)
• MOPP - (i/a) Mission-Oriented Protective Posture
• MORP - (a) Meteorite Observation and Recovery Project
• MORS - (i) Military Operations Research Society
• MOS - (i) Military Occupational Specialty - (a) Mit Out Sound / Motor Only Sync - (i) Mobile Object System - Model Output Statistics - Multiplayer Online Services
• MOSFET - (a) Metal-Oxide-Semiconductor Field-Effect Transistor
• MOSS - (p) MObile Submarine Simulator - (a) Moving Object Support System
• MOT - (i) Ministry of Transport (UK)
• MOTA - (i) Member of the Orthodontic Technicians Association
• MOTESS - (a) Moving Object and Transient Event Search System
• MOTO - (a) Mail Order / Telephone Order - Master of the obvious
• MOU - (i) Memorandum Of Understanding
• MOUT - (i) Military Operations in Urban[ized] Terrain
• MOVES - (a) Modeling, Virtual Environments, and Simulation Institute
• MOW - (i) Maintenance of way (also MW)
• MOZ - (s) Mozambique (ISO 3166 trigram)

MP

• MP - (i) Magic points - (s) Mauritius (FIPS 10-4 country code) - (i) Member of Parliament - Military Police - Missouri Pacific - (s) Northern Mariana Islands (postal symbol; ISO 3166 digram)
• mPa - (s) Millipascal
• MPa - (s) Megapascal
• MPA - (i) Maritime Patrol Aircraft - Master of Public Administration
• MPAA - (i) Motion Picture Association of America
• MPC - (i) Minor Planet Center - Minor Planet Circular
• MPEC - (i) Minor Planet Electronic Circular
• MPEG - (a) Motion Pictures (Coding) Experts Group
• MPEV - (i) Multi-Purpose Engineering Vehicle
• MPF - (i) Maritime Prepositioning Force
• MPFC - (i) Medial PreFrontal Cortex
• MPMC - (i) Medial PreMotor Cortex
• MPSI - (i) Member of the Pharmaceutical Society of Ireland
• MPSoC - (i) MultiProcessor System-on-Chip
• MPSRON - (p) Maritime Propositioning Ship Squadron

MQ

• MQ - (s) Martinique (ISO 3166 digram) - Midway Islands (FIPS 10-4 territory code) - MechQuest

MR

• mr - (s) Marathi language (ISO 639-1 code)
• MR - (s) Mauritania (FIPS 10-4 country code; ISO 3166 digram)
• MR-ATGW - (i) Medium-Range Anti-Tank Guided Weapon
• MRAV - (i) Multi-Role Armoured Vehicle
• MRBM - (i) Medium Range Ballistic Missile
• MRC - (i) Maintenance Requirements Card
• MRD - (i) Motorized Rifle Division
• MRE - (i) Meal Ready to Eat (U.S. military rations)
• MRGW - (i) Medium-Range Guided Weapon
• mri - (s) Māori language (ISO 639-2 code)
• MRI - (i) Magnetic Resonance Imaging
• MRL - (i) Multiple Rocket Launcher
• MRO - (i) Maintenance, Repair and Operating - Mars Reconnaissance Orbiter - (s) Mauritanian ouguiya (ISO 4217 currency code)
• MRPharmS - (i) Member of the Royal Pharmaceutical Society (Great Britain)
• MRR - (i) Maximum Rock and Roll - Minimum-Risk Route - My Restaurant Rules
• MRS - (i) Magnetic Resonance Spectroscopy
• MRSA - (i) Methicillin-resistant Staphylococcus aureus
• MRT - (s) Mauritania (ISO 3166 trigram)
• MRTFB - (i) U.S. Major Range and Test Facility Base

MS

• ms - (s) Malay language (ISO 639-1 code) - Millisecond
• mS - (s) Millisiemens
• Ms - (s) Megasecond
• MS - (i) mano sinistra (Latin, "left hand") - (p) manuscript - (i) Master of Science - (s) Megasiemens - (p) Microsoft (sometimes M$) - (s) Mississippi (postal symbol) - Montserrat (ISO 3166 digram) - (i) Multiple Sclerosis
• M&S - (i) Modelling & Simulation - Marks & Spencer
• msa - (s) Malay language (ISO 639-2 code)
• MSB - (i) Main Support Battalion - Most Significant Bit (or Byte)
• MSD - (i) Minimum Safe Distance
• MSDB - (i) Multi Source Data Base
• MSDE - (i) Maryland State Department of Education - (p) Microsoft Data[base] Engine - Microsoft SQL Server 2000 Desktop Engine - (i) Military Scenario Development Environment - Mission Simulation Dynamic Engine
• MSDL - (i) Military Scenario Definition Language
• MSE - (i) Multiple Subscriber Element
• MSEC - (p) Message Security Encryption Code ("emm-sec")
• MSG - (i) MonoSodium Glutamate, Madison Square Garden
• MSH - (i) Medium Support Helicopter - Mount Saint Helens
• MSI - (i) Micro-Star International - (p) Multispectral imagery
• MSIE - (i) Microsoft Internet Explorer - Master of Science in Industrial Engineering
• MSL - (i) Mars Science Laboratory - Mean Sea Level - (p) Missile
• MSLP - (i) Mean Sea Level Pressure
• MSM - (i) Mount St Mary's School
• MSN - (a) Microsoft Network - (i) Master of Science in Nursing
• msnbc.com - (a) msnbc.com - News website
• MSNBC - (a) Microsoft National Broadcasting Company Cable news channel
• MSO - (i) Multiple System Operator
• MSR - (i) Main Supply Route - Module Service Record - (s) Montserrat (ISO 3166 trigram) - (i) Motor Schlepp Regulung
• MSSA - (i) Methicillin-susceptible Staphylococcus aureus
• MST - (i) Madison Symmetric Torus - Mountain Standard Time (UTC-7 hours)
• MST3K or MST3k - (i) Mystery Science Theater 3000

MT

• mt - (s) Maltese language (ISO 639-1 code)
• mT - (s) Millitesla
• Mt - (s) Meitnerium
• MT - (s) Malta (FIPS 10-4 country code; ISO 3166 digram) - Megatesla - Montana (postal symbol) - (i) Motor Transport (military)
• MTA - (i) - Metropolitan Transportation Authority
• MTBF - (i) Mean Time Between Failures
• MTF - (i) Medical Treatment Facility - Message Text Format
• MTG - (i) Magic: The Gathering
• MTL - (s) Maltese lira (ISO 4217 currency code) - (i) Mean Tide Level (nautical charts)
• MTM - (i) Methods-Time Measurement
• MTOE - (p) Modified Table of Organization and Equipment ("emm-toe")
• MTP – (i) Maritime Tactical Publication - Materiel Transfer Plan - Mission Training Plan
• MTQ - (s) Martinique (ISO 3166 trigram)
• MTR - (i) Main and Tail Rotor (helicopter type) - Military-Technological Revolution
• MTS - (i) Maintenance Training System - Michigan Terminal/Timesharing System - Movement Tracking System - Multichannel television sound - Multi-Technical Services
• MTT - (p) Methylthiazol tetrazolium (assay)
• MTU - (i) Tankovei Mostoukladchik (Russian Танковый Мостоукладчик, "Tank Bridge-Layer") †
• MTV - (i) MainosTeleVisio (Finnish commercial TV company) - Music TeleVision
• MTVL - (i) Mobile Tracked Vehicle, Light
• MTWS - (i) MAGTF Tactical Warfare System

MU

• MU - (s) Mauritius (ISO 3166 digram) - Oman (FIPS 10-4 country code; from Muscat)
• MUA - (i) Meritorious Unit Award - Military Utility Assessment
• MUR - (s) Mauritius rupee (ISO 4217 currency code)
• MUS - (s) Mauritius (ISO 3166 trigram)

MV

• mV - (s) Millivolt
• MV - (s) Maldives (FIPS 10-4 country code; ISO 3166 digram) - Megavolt - (i) Motor Vehicle - Motor Vessel
• MVR - (s) Maldivian rufiyaa (ISO 4217 currency code)

MW

• mW - (s) Milliwatt
• MW - (i) Maintenance of way (also MOW) - (s) Malawi (ISO 3166 digram) - (i) Medium Wave (radio) - (s) Megawatt
• MWC - (i) Maritime Warfare Centre (various nations)
• MWESH - (p) Machismo Wizards Extended SHelter (operating system)
• MWI - (s) Malawi (ISO 3166 trigram)
• MWK - (s) Malawi kwacha (ISO 4217 currency code)
• MWOA - (i) Mount Wilson Observatory Association
• MWR - (i) Morale, Welfare, and Recreation

MX

• MX - (a) Mail Exchange - (s) Mexico (FIPS 10-4 country code; ISO 3166 digram) - (p) Missile eXperimental
• MXN - (s) Mexican peso (ISO 4217 currency code)

MY

• my - (s) Burmese language (ISO 639-1 code)
• MY - (s) Malaysia (FIPS 10-4 country code; ISO 3166 digram)
• mya - (s) Burmese language (ISO 639-2 code) - (i) million years ago
• MYOB - (i) Mind Your Own Business
• MYR - (s) Malaysian ringgit (ISO 4217 currency code)
• MYS - (s) Malaysia (ISO 3166 trigram)
• MYT - (s) Mayotte (ISO 3166 trigram)

MZ

• MZ - (i) Mach-Zehnder (interferometer) - (s) Magnetic Azimuth - (i) Move, Zig (Zero Wing) - (s) Mozambique (FIPS 10-4 country code; ISO 3166 digram)
• MZN - (s) Mozambique metical (ISO 4217 currency code)