| MH | Medical History | In English | → Medicine → History |
| MHF | Medium High Frequency | In English | → Telecommunications |
| MHI | Mitsubishi Heavy Industries | In English | → Mechanical engineering → Spaceflight engineering, astronautics |
| MHITR | Mitsubishi Heavy Industries Technical Review | In English | → Serial publications, periodicals → Vehicle engineering |
| MHLA | Maritimes Health Libraries Association = ABSM | Association des Bibliothèques de la Santé des Maritimes | In French |
In English | → Libraries → Associations → Medicine → 6295 |
| MHP | Methylphenidate | In English | → Chemical technology |
| MHRA | Medicines and Healcare products Regulatory Agency | In French | → Public administration, government → Public health and hygiene |
| MHV | Miniature Homing Vehicle | In English | → Vehicle engineering |
| MI | Malleable Iron | In English | → Metallurgy |
| MIAT | Mongolyn Irgenii Agaaryn Teever = МИАТ | Монголын Иргэний Агаарын Тээвэр | In Mongolian |
In Mongolian | → Aeronautics, aircraft → Transport and postal services |
| MIAU | Multiple Internet Agents for User-adaptive Decision | In English | → Networks, communication → Telecommunications |
| MIB | Materials and systems Institute of Bordeaux | In English | → 620 |
| MIC | Monolithic Integrated Circuit | In English | → Electronics |
| MICIP | Ministerio de Comercio Exterior, Industrialización, Pesca y Competitividad | In Spanish | → Central administration → Trade → Industry, industrial policy → Fishing, hunting |
| MICNS | Modular Integrated Communication and Navigation System | In English | → Telecommunications |
| MICOM | Missile Command | In English | → Military engineering |
| MICSTRAN | Microscopic Simulator Model for Traffic Networks | In English | → Computer simulation → Transport and postal services |
| MIDD | Maternally Inherited Diabetes and Deafness | In English | → Pathology |
| MIDSIM | Midcourse Exoatmospheric Event-Based Simulator | In English | → Astronomy → Spaceflight engineering, astronautics |
| MiElC | Military Electronics Countermeasures | In English | → Serial publications, periodicals → Military engineering → Electronics |
| MiEng | Microelectronic Engineering | In English | → Serial publications, periodicals → Electronics |
| MIEWF | Master Integrated Engineering Work File | In English | → Engineering, technology |
| MIF | Mechanical Integration Frame | In English | → Mechanical engineering |
| MIGD | Million Imperial Gallons per Day | In English | → Engineering, technology |
| MII | Maisons Individuelles Isolées | In French | → Building → Energy economics |
| MiI | Microelectronics International | In English | → Serial publications, periodicals → Electronics |
| MILA | Merritt Island Launch Area | In English | → Spaceflight engineering, astronautics |
| MILCOMSAT | Military Communications Satellite | In English | → Military engineering → Spaceflight engineering, astronautics |
| MILS | Missile Impact Location System | In English | → Military engineering |
| MILSTAR | Military Strategic And Tactical Relay System | In English | → Military engineering → Spaceflight engineering, astronautics |
| MILSTD | Military Standard | In English | → Standardization → Military engineering |
| MIM | Maîtrise d'Ingénierie Mathématique | In French | → Higher education, universities → Mathematics → Engineering, technology |
| MIMOSA | Migration et Mobilité - Sémantique et Applications | In French | → Computer-based techniques → Telecommunications → Semiotics |
| MIMS | Medical Information Management System | In English | → Management → Medicine |
| MIOM | Mâchefer d'Incinération d'Ordures Ménagères | In French | → Environmental technology, water supply, waste management |
| MIPIR | Missile Impact Pointing Imaging Radar | In English | → Military engineering |
| MIPR | Military Intergovernmental Purchase Request | In English | → 34745 → Military engineering |
| MIPS | Merritt Island Press Site | In English | → Newspapers, journalism → Spaceflight engineering, astronautics |
| MiRe | Microelectronics Reliability | In English | → Serial publications, periodicals → Electronics |
| MIRE | Mesure et système d’Information des Réseaux Électriques | In French | → Electrical engineering |
| MIRV | Multiple Independently Targetable Reentry Vehicles | In English | → Spaceflight engineering, astronautics |
| MisSp | Missiles Spacecraft | In English | → Serial publications, periodicals → Military engineering → Spaceflight engineering, astronautics |
| MISTRAM | Missile Trajectory Measurement | In English | → Military engineering |
| MIT | Massachusetts Institute of Technology | In English | → Specialized or (poly)technical colleges → Engineering, technology |
| MITAS | Missile Threat Analysis Simulation | In English | → Military engineering |
| MITIL | MIT (Massachusetts Institute of Technology) Instrumentation Laboratory | In English | → Research institutes → Specialized or (poly)technical colleges → Engineering, technology |
| MITOC | Missile Intercom Technical Operational Communication | In English | → Military engineering → Telecommunications |
| MITSIM | Microscopic Traffic Simulator | In English | → Computer simulation → Transport and postal services |
| MIV | Menslike Immuniteitsgebreksvirus = VIH | Virus de l'Immunodéficience Humaine | In French = HIV | Human Immunodeficiency Virus | In English = VIH | Virus d'Inmunodeficencia Humana | In Asturian = VIH | Vírus da imunodeficiência humana | In Portuguese = VIDH | Virus Immunitarii Defectus Humanae | In Latin = ŽIV | Žmogaus Imunodeficito Virusas | In Lithuanian = ХИВ | Хумане имунодефицијенције | In Serbian = HIV | Humani Imunodeficientni Virus | In Slovenian = ВИЧ | Вирус иммунодефицита человека | In Russian = GIB | Giza Immunoeskasiaren Birusa | In Basque |
In Afrikaans | → Virology → Immunology and allergy → Infectious diseases |
| MIVB | Maatschappij voor het Intercommunaal Vervoer te Brussel = STIB | Société des Transports Intercommunaux de Bruxelles | In French |
In Dutch | → Organizations and associations → Transport and postal services |
| MJ | Mechanical Joint | In English | → Mechanical engineering |
| MLC | Mobile Launcher Computer | In English | → Hardware → Spaceflight engineering, astronautics |
| MLF | MDM Launch Forward | In English | → Spaceflight engineering, astronautics |
| MLG | Main Landing Gear | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MLGD | Main Landing Gear Door | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MLGS | Microwave Landing Guidance System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MLI | Modulation de Largeur d'Impulsion | In French | → Electrical engineering |
| MLP | Mobile Launch(er) Platform | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MLR | Monodisperse Latex Reactor | In English | → Chemical technology |
| MLS | Microwave Landing System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MLV | Medium-Lift Launch Vehicle | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MLV | Medium Launch Vehicle | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MLW | Maximum Landing Weight | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MM&TS | Master Manufacturing and Test Schedule | In English | → Engineering, technology |
| MMA | Moving Mechanical Assembly | In English | → Mechanical engineering |
| MMA | Methyl Methacrylat | In English | → Chemistry → Chemical technology |
| MMA | Mobile Marketing Association | In English | → Organizations and associations → 6591 |
| MMAS | Mechanized Material Accountability System | In English | → Maintenance and logistics → Mechanical engineering |
| MMAS | Mathematical Methods in the Applied Sciences | In English | → Serial publications, periodicals → Mathematics → Engineering, technology |
| MMC | Midmotor Controller | In English | → Vehicle engineering |
| MMC | Metal Matrix Composite | In English | → Metallurgy |
| MMC | Master Microprocessor Control | In English | → Hardware → Electronics |
| MMCA | Midmotor Controller Assembly | In English | → Vehicle engineering |
| MMG | Multimedia Management Group | In English | → Management → Telecommunications |
| MMH | Monomethylhydrazine | In English | → Chemical technology |
| MMI | Medicus Mundi Italia | In Italian | → Organizations and associations → Medicine |
| MMIA | Monolithic Microwave Integrated Amplifier | In English | → Electronics |
| MMIC | Monolithic Microwave Integrated Circuit | In English | → Electronics |
| MMIC | Millimeter-Wave Monolithic Integrated Circuit | In English | → Electronics |
| MMLS | Martin Marietta Launch Services | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MMM | Myélofibrose avec Métaplasie Myéloïde | In French | → Blood and circulatory system → Pathology |
| MMP | Materials and Manufacturing Processes | In English | → Serial publications, periodicals → 620 |
| MMRS | Manned Military Recovery System | In English | → Military engineering |
| MMS | Multimission Spacecraft | In English | → Spaceflight engineering, astronautics |
| MMS | Multimission Modular Spacecraft | In English | → Spaceflight engineering, astronautics |
| MMS | Mission Modular Spacecraft | In English | → Spaceflight engineering, astronautics |
| MMS | Medical Mission Sisters | In English | → Roman catholic church → Medicine |
| MMS | Multimedia Messaging Service | In English | → Telecommunications |
| MMS | Multi-mission Modular Spacecraft | In English | → Spaceflight engineering, astronautics |
| MMSC | Multimedia Messaging Service Center | In English | → Telecommunications |
| MMSE | Mini-Mental State Examination | In English | → Medicine |
| MMT | Médecins Maîtres-Toile | In French | → Networks, communication → Organizations and associations → Medicine |
| MMTV | Mouse Mammary Tumor Virus | In English | → Virology → Oncology |
| MMW | Münchener Medizinische Wochenschrift | In German | → Serial publications, periodicals → Medicine |
| MNOS | Metal Nitride Oxide Semiconductor | In English | → Electronics |
| MNPQ | Messen, Normen, Prüfen und Qualitätssicherung | In German | → Quality management → Engineering, technology |
| MO | Manned Orbiter | In English | → Spaceflight engineering, astronautics |
| MOAB | Massive Ordnance Air Blast | In English | → Military engineering |
| MoBiMed | Molekulare Bildgebung in der Medizin | In German | → Biological sciences → Medicine |
| MOCA | Modification des connaissances, attitudes et/ou comportements des usagers en faveur de la sécurité routière | In French | → Vehicle engineering → Transport and postal services |
| MOCF | Mutuelle de l'Orphelinat des Chemins de Fer Français | In French | → Transport and postal services |
| MOCN | Machine-Outil à Commande Numérique | In French | → Computer-based techniques → Mechanical engineering |
| MODE | Middeck Zero-Gravity Dynamics Experiment | In English | → Spaceflight engineering, astronautics |
| MODS | Military Orbital Development System | In English | → Military engineering → Spaceflight engineering, astronautics |
| MODY | Maturity-Onset Diabetes of the Young | In English | → Pathology |
| MOE | Munduko Osasun Erakundea = MOS | Monda Organiz(aĵ)o pri Sano | In Esperanto = WHO | World Health Organization | In English = OMS | Organisation Mondiale de la Santé | In Esperanto = OMS | Organizzazione Mondiale della Sanità | In Italian = WGO | Wêreldgesondheidsorganisasie | In Afrikaans = OMS | Organización Mundial de la Salú | In Asturian = СЗО | Световната здравна огранизация | In Bulgarian = SZO | Světová zdravotnická organizace | In Czech = OMS | Organització Mundial de la Salut | In Catalan = OMS | Organización Mundial de la Salud | In Spanish = MTO | Maailma Terviseorganisatsioon | In Estonian = OMS | Organisacion mondiâla de la sandât | FRP = OMS | Organización Mundial da Saúde | In Galician = SZO | Svjetska zdravstvena organizacija | In Croatian = RTD | Rêxistina Tendurustiyê ya Dinyayê | In Kurdish = UMS | Urganizazziun mundiala da la Santaa | In Lombard = PSO | Pasaulio sveikatos organizacija | In Lithuanian = PVO | Pasaules veselības organizācija | In Latvian |
In Basque | → United Nations → Medicine |
| MOF | Manned Orbital Flight | In English | → Spaceflight engineering, astronautics |
| MOFA | Ministry of Food and Agriculture | In English | → Central administration → Agricultural sciences → Food technology |
| MOL | Manned Orbital Laboratory | In English | → Research institutes → Spaceflight engineering, astronautics |
| MOP | Made-to-Order Production | In English | → Engineering, technology |
| MOPA | Master Oscillator Power Amplifier | In English | → Electrical engineering |
| MOPIS | Missile Operations Intercommunications System | In English | → Military engineering |
| MOPS | Missile Operations | In English | → Military engineering |
| MOPS | Military Operation Phone System | In English | → Military engineering → Telecommunications |
| MOR | Manufacturing Order Record | In English | → Engineering, technology |
| MOR | Manufacturing Operations Record | In English | → Engineering, technology |
| MORD | Medical Operations Requirements Document | In English | → Medicine |
| MORL | Manned Orbiting Research Laboratory | In English | → Research institutes → Spaceflight engineering, astronautics |
| MOS | Metal Oxide Semiconductor | In English | → Electronics |
| MOS | Monda Organiz(aĵ)o pri Sano = MOE, WHO, OMS, WGO, СЗО, SZO, MTO, RTD, UMS, PSO, PVO (look above) |
In Esperanto | → United Nations → Medicine |
| MOSES | Mobile Safety System | In English | → Engineering, technology |
| MOSFET | Metal-On-Silicon Field-Effect Transistor | In English | → Electronics |
| MOSPO | Mobile Satellite Photometric Observatory | In English | → Observatories → Spaceflight engineering, astronautics |
| MOSS | Manned Orbital Space Station | In English | → Spaceflight engineering, astronautics |
| MotZe | Motortechnische Zeitschrift | In German | → Serial publications, periodicals → Mechanical engineering → Vehicle engineering |
| MOX | Mixed OXyde fuel | In English | → Nuclear technology |
| MPBS | Main Power Bus Supply | In English | → Electrical engineering |
| MPD | Main Dc Power Distributor | In English | → Electrical engineering |
| MPFD | Microdevices: Physics and Fabrication Technologies | In English | → Serial publications, periodicals → Mechanical engineering |
| MPGN | Membranoproliferative Glomerulonephritis | In English | → Pathology |
| MPH | Methodist Publishing House (www.mph.org.uk) | In English | → Graphic industries, printing, publishing → Protestant churches |
| MPH | Master of Public Health | In French | → Higher education, universities → Public health and hygiene |
| MPH | Mennonite Publishing House (www.mph.org) | In English | → Modern spiritual movements → Graphic industries, printing, publishing |
| MPI | Midi-Pyrénées Innovation | In French | → Regional administration → Engineering, technology |
| MPL | Mechanical Parts List | In English | → Maintenance and logistics → Mechanical engineering |
| MPL | Minimum Power Level | In English | → Electrical engineering |
| MPLS | Multi Protocol Label Switching | In English | → Networks, communication → Food technology |
| MPM | Manipulator Positioning Mechanism | In English | → Mechanical engineering |
| MPMP | Mechanical Parts, Material & Process(es) | In English | → Maintenance and logistics → Mechanical engineering |
| MPOC | Maladie Pulmonaire Obstructive Chronique | In French | → Pathology |
| MPOR | Master Power-On Reset | In English | → Electrical engineering |
| MPP | Manufacturing Process Procedure | In English | → Engineering, technology |
| MPPE | (Integrated Research in) Materials, Processing and Product Engineering | In English | → Engineering, technology |
| MPRAS | Multipath Redundant Avionics Suite | In English | → Aeronautics, aircraft |
| MPS | Materials Processing Science | In English | → 620 |
| MPS | Materials Processing In Space | In English | → 620 → Spaceflight engineering, astronautics |
| MPS | Material Processing Specification | In English | → Vehicle engineering |
| MPS | Material Processing Satellite | In English | → 620 → Spaceflight engineering, astronautics |
| MPS | Maneuvering Propulsion Subsystem | In English | → Vehicle engineering |
| MPS | Main Propulsion System | In English | → Vehicle engineering |
| MPS&P | Material Processing Specifications and Procedures | In English | → 620 |
| MPT | Main Propulsion Test | In English | → Vehicle engineering |
| MPT | Ministry of Posts and Telecommunications | In English | → Organizations and associations → Telecommunications → Transport and postal services |
| MPTA | Main Propulsion Test Article | In English | → Vehicle engineering |
| MPTF | Main Propulsion Test Facility | In English | → Vehicle engineering |
| MPTP | Main Propulsion Test Program | In English | → Vehicle engineering |
| MPVA | Main Propellant Valve Actuator | In English | → Spaceflight engineering, astronautics |
| MR | Magnetska ili magnetna rezonancija | In Croatian | → Medicine → Nuclear, atomic, and molecular physics |
| MR | Magyar Rádió | In Hungarian | → Telecommunications |
| MRA | Mechanical Readiness Assessment | In English | → Mechanical engineering |
| MRBM | Medium-Range Ballistic Missile | In English | → Military engineering |
| MRBT | Maintenance Réseaux-Bureautique-Télématique | In French | → Computer science → Telecommunications |
| MRC | Medical Research Council | In English | → Organizations and associations → Medicine |
| MRD | Minimal Residual Disease | In English | → Pathology |
| MRF | Missile Repair Facility | In English | → Military engineering |
| MRI | Magnetic Resonance Imagery = IRM | Imagerie par Résonance Magnétique | In French |
In English | → Medicine → Nuclear, atomic, and molecular physics |
| MRL | Missile Reference Line | In English | → Military engineering |
| MRMS | Mobile Remote Manipulator System | In English | → Mechanical engineering |
| MRP | Missile Reference Plane | In English | → Military engineering |
| MRR | Manufacturing Readiness Review | In English | → Maintenance and logistics → Engineering, technology |
| MRSR | Mars Rover Sample Return | In English | → Planets and satellites → Spaceflight engineering, astronautics |
| MRT | Magnetresonanz-Tomografie = MRT | Magnetresonanstomografi | In Swedish |
In German | → Medicine → Nuclear, atomic, and molecular physics |
| MRT | Magnetresonanstomografi = (look above) |
In Swedish | → Medicine → Nuclear, atomic, and molecular physics |
| MRT | Macedonian Radio-Television (www.mkrtv.com.mk) = МРТ | Македонска радио-телевизија | In Macedonian = KVV | Kevarzhe Vannielouriezh Vreizh | In Breton = SBV | Société Bretonne de Vexillologie | In French |
In English | → Telecommunications |
| MRZ | Medizinisches Rechenzentrum | In German | → Computer science → Medicine |
| MS | Multiple Sclerosis | In English | → Neurology |
| MS | Ministerul Sănătăţii | In Romanian | → Central administration → Public health and hygiene |
| MS | Mobile Station | In English | → Telecommunications |
| MS | Machine Screw | In English | → Mechanical engineering |
| MS | Material Specification | In English | → Maintenance and logistics → 620 |
| MS | Mechanical System | In English | → Mechanical engineering |
| MS/MS | Material Science and Manufacturing in Space | In English | → Engineering, technology → Spaceflight engineering, astronautics |
| MSA | Main Bus Solar Array | In English | → Energy economics |
| MSA | Mutualité Sociale Agricole | In French | → Insurance → Agricultural sciences |
| MSBCIA | Macedonian Society for Basic, Clinical Immunology and Allergology | In English | → Organizations and associations → Immunology and allergy |
| MSBLS | Microwave Scan-Beam Landing System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| MSBM | Maîtrise de Sciences Biologiques et Médicales | In French | → Higher education, universities → Biological sciences → Medicine |
| MSC | Mobile Service Switching Center | In English | → Telecommunications |
| MSCB | Manufacturing Status Control Board | In English | → Maintenance and logistics → Engineering, technology |
| MSD | Missile Systems Division | In English | → Military engineering |
| MSDT | Multiple Shuttle Data Tape | In English | → Data → Spaceflight engineering, astronautics |
| MSE | Mission Support Equipment | In English | → Engineering, technology |
| MSE | Mission Staff Engineer | In English | → Engineering, technology |
| MSE | Medical Support Equipment | In English | → Medicine |
| MSE | Mechanical Support Equipment | In English | → Mechanical engineering |
| MSE | Manned Space Flight Engineer | In English | → Spaceflight engineering, astronautics |
| MSEng | Materials Science and Engineering | In English | → Serial publications, periodicals → 620 |
| MSF | Materials Science Forum | In English | → Serial publications, periodicals → 620 |
| MSF | Manned Space Flight | In English | → Spaceflight engineering, astronautics |
| MSF | Médecins Sans Frontières | In French | → Organizations and associations → Medicine |