| AGM | Aorto-gonadomesonephros | In English | |
| AGM | Absorbent Glass Mat | In English | |
| AGMA | American Gear Manufacturer's Association | In English | → Organizations and associations → Engineering, technology |
| AGMC | Aerospace Guidance and Metrology Center | In English | |
| AGN | Active Galactic Nucleus | In English | → Cosmology |
| AGOA | African Growth and Opportunity Act | In English | |
| AGOES | Advanced Geosynchronous Observation Environment | In English | |
| AGORA | Access to Global Online Research in Agriculture | In English | → Libraries → Agricultural sciences |
| AGOSS | Automated Ground Operations Scheduling System | In English | |
| AGP | Accelerated Graphics Port | In English | → Graphical processing → Image processing |
| AGp | Annals of Geophysics | In English | → Serial publications, periodicals → Geophysics |
| AGR | Advanced Gas Cooled Reactor | In English | → Nuclear technology |
| AGREE | Advisory Group in Reliability of Electronic Equipment | In English | → Electronics |
| AGREE | Appraisal of Guidelines REsearch and Evaluation | In English | → Medicine |
| AGS | ASPS Gimbal System | In English | |
| AGS | Antigravity Suit | In English | |
| AGS | Abort Guidance System | In English | |
| AGT | Adaptive Guidance Throttling | In English | |
| AGT | Atmospheric Glow Technologies | In English | |
| AGTS | Australasian Gene Therapy Society (www.agts.org.au) | In English | → Organizations and associations → Biotechnology → Medicine |
| AGTS | Advanced Gunnery Training System | In English | |
| AGTS | Assemblies of God Theological Seminary (www.agts.edu) | In English | → Organizations and associations → Social sciences |
| AGU | American Geophysical Union | In English | → Earth sciences |
| AGU | Address Generation Unit | In English | → Computer science |
| AGUFM | American Geophysical Union Fall Meeting Abstracts | In English | → Serial publications, periodicals → Geophysics |
| AGUSM | American Geophysical Union Spring Meeting Abstracts | In English | → Serial publications, periodicals → Geophysics |
| AH | Authentication Header | In English | |
| AH | Art History | In English | → Serial publications, periodicals → Arts → History |
| AHA | American Historical Association | In English | → Associations → History |
| AHA | American Humane Association (www.americanhumane.org) | In English | → Associations |
| AHA | Accelerated Hub Architecture | In English | → Networks, communication |
| AHCS | Advanced Helicopter Control System | In English | |
| AHDA | Animal Health Distributors Association (www.ahda.org.uk) | In English | → Associations → Veterinary medicine |
| AHEAD | Animal Health/Emerging Animal Diseases | In English | → Veterinary medicine |
| AHES | Archive for History of Exact Sciences | In English | → Serial publications, periodicals → Mathematics and natural sciences → History |
| AHI | Animal Health Institute (www.ahi.org) | In English | → Veterinary medicine |
| AHI | Artificial Horizon Indicator | In English | |
| AHILA | Association for Health Information and Libraries in Africa = AIBSA | Association pour l'Information et les Bibliothèques de Santé en Afrique | In French |
In English | → Libraries → Associations → Medicine |
| AHIS | Animal Health Information Specialists | In English | → Veterinary medicine |
| AHIS | Atlantic Health Information Systems | In English | |
| AHL | American Hockey League | In English | → Sport, physical exercises |
| AHL | Aboriginal Hostels Limited | In English | |
| AHL | American Home Loans | In English | → Accommodation |
| AHM | Automatic Hold Mode | In English | |
| AHP | Analytical Hierarchy Process | In English | |
| AHR | Ablative Heat Rate | In English | |
| AHR | American Historical Review | In English | → Serial publications, periodicals → History |
| AHRB | Arts and Humanities Research Board | In English | → Arts → Language, linguistics, literature |
| AHRC | Arts and Humanities Research Council | In English | → Arts → Language, linguistics, literature |
| AHRS | Attitude Heading Reference System | In English | → Spaceflight engineering, astronautics |
| AHS | Aft Heat Shield | In English | |
| AHS | Agricultural History Society | In English | → Organizations and associations → Agricultural sciences → History |
| AHS | Association for Humanist Sociology | In English | → Associations → Sociology |
| AHSJ | American Helicopter Society Journal | In English | → Serial publications, periodicals → Aeronautics, aircraft |
| aHUS | Atypical Hemolytic Uremic Syndrome | In English | → Blood and circulatory system → Pathology |
| AI | Artificial Insemination | In English | → Reproductive biology |
| AI | Action Item | In English | |
| AI | Airspeed Indicator | In English | |
| AI | Altimeter Indicator | In English | |
| AI | Altitude Indicator | In English | |
| AI | Anti-Icing | In English | |
| AI | Artificial Intelligence = AI | Artificiële Intelligentie | In Dutch = KI | Kunstmatige Intelligentie | In Dutch = VI | Vještačka inteligencija | In Bosnian = IA | Intelligència artificial | In Catalan = KI | Künstliche Intelligenz | In German = AI | Artefarita Inteligenteco | In Esperanto = IA | Intelligence Artificielle | In French |
In English | → Artificial intelligence |
| AI | Associate Investigator | In English | |
| AIA | Aircraft Industries Association (www.aia-aerospace.org) | In English | → Organizations and associations → Aeronautics, aircraft |
| AIA | Association for Industrial Archaeology (www.industrial-archaeology.org.uk) | In English | → Associations → Industry, industrial policy → Archeology |
| AIAA | American Institute of Aeronautics and Astronautics | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| AIAAJ | American Institute of Aeronautics and Astronautics Journal | In English | → Serial publications, periodicals → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| AIASJ | American Institute of Aeronautics and Astronautics Student Journal | In English | → Serial publications, periodicals → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| AIC | Australian Islamic College | In English | → Education → Islam |
| AIC | Akaike Information Criterion | In English | |
| AIC | Application Integration Components | In English | → Computer science |
| AICAR | Aminoimidazole-Carboxamide-Ribofuranoside | In English | → Biochemistry, biophysics |
| AICC | Action Item Control Card | In English | |
| AICE | American Institute of Chemical Engineers | In English | |
| AIChE | American Institute of Chemical Engineers | In English | → Chemical technology |
| AICP | Aerodynamic Instrumental Coefficient Package | In English | → Aerodynamics |
| AICS | Action Item Closeout Sheet | In English | |
| AICSP | Analog Integrated Circuits and Signal Processing | In English | → Serial publications, periodicals → Electronics |
| AID | Abbreviated Item Description | In English | |
| AID | Action Item Disposition | In English | |
| AID | Analog Input Differential | In English | |
| AID | Audit Item Disposition | In English | |
| AIDA | Agressive Intermediate Duct Activities | In English | |
| AIDB | Animation Industry Database | In English | → Cinema, movies |
| AIDE | Adaptive Integrated Driver | In English | → Vehicle engineering → Transport and postal services |
| AIDE | Aerospace Installation Diagnostic Equipment | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| AIDMO | Arab Industrial Development and Mining Organization | In English | → Industry, industrial policy → Mining |
| AIDS | Airborne Integrated Data System | In English | → Data → Aeronautics, aircraft |
| AIDS | Acquired Immune Deficiency Syndrome = SIDA | Syndrome d'Immuno-Déficience Acquise | In French = VIGS | Verworwe Immuniteitsgebreksindroom | In Afrikaans = SIDA | Síndrome de Inmuno-Deficiencia Adquirida | In Occitan = SIDA | Sindromo di Imuno-Defekteso Aquirita | In Ido = AIDS | Akirita Imuno-Deficita Simptomaro | In Esperanto = SIDA | Sindrome d'inmunodefizienzia aquirita | In Aragonese = СПИН | Синдром на придобитата имунна недостатъчност | In Bulgarian = QİÇS | Qazanılmış İmmun Çatışmazlığı Sindromu | In Azerbaijani = SIDA | Síndrome d'Immunodeficiència Adquirida | In Catalan = HIES | Hartutako Immuno Eskasiaren Sindromea | In Basque = SIDA | Síndrome de Inmunodeficiencia Adquirida | In Spanish = SEIF | Siondróm Easpa Imdhíonachta Faighte | In Irish = AIDS | Annlochd Inneamh Dìon-Slàinte | In Scottish Gaelic = ՁԻԱՀ | Ձեռքբերովի Իմունային Անբավարվածության Համախտանիշ | In Armenian = SCDI | Syndromis Comparatis Defectu Immunitatis | In Latin = 에이즈 | 후천성 면역 결핍 증후군 | In Korean = შიდსი | შეძენილი იმუნური დეფიციტის სინდრომი | In Georgian = СИДА | Синдромот на стекнат имунолошки дефицит | In Macedonian = СИДА | синдром стеченог имунолошког дефицита | In Serbian = AIDS | Akvirírani imúnski deficítni sindróm | In Slovenian = СПИД | Синдром приобретённого иммунного дефицита | In Russian = SIDA | Sindromul Imunodeficienţei Autodobândite | In Romanian = UHCW | Unquy hark'aypa chaskisqa waqlliynin | In Quechua = SIDA | Síndrome da imunodeficiência adquirida | In Portuguese = AIDS | Hội chứng Suy giảm Miễn dịch Mắc phải | In Vietnamese = СНІД | Cиндром набутого імунодефіциту | In Ukrainian = AIDS | Alınğan İmmun Defisit Síndromı | In Tatar = UKIMWI | Upungufu wa Kinga Mwilini | In Swahili |
In English | → Immunology and allergy → Infectious diseases |
| AIE | European Association of Electrical Contractors | In English | → Associations → Electrical engineering |
| AIEE | American Institute of Electrical Engineers | In English | → Organizations and associations → Electrical engineering |
| AIEP | Academic Intensive English Program | In English | → Education → Linguistics |
| AIF | Auto Increment Field | In English | → Data |
| AIF | Apoptosis Inhibitor Factor | In English | → Biochemistry, biophysics → Oncology |
| AIF | American India Foundation (www.aifoundation.org) | In English | → Foundations → International relations |
| AIF | Animal Industry Foundation | In English | → Foundations → Agricultural sciences |
| AIFF | Audio Interchange File Format | In English | → Computer-based techniques → Telecommunications |
| AIFRB | American Institute of Fisheries Research Biologists (www.aifrb.org) | In English | → Organizations and associations → Biological sciences → Fishing, hunting |
| AiG | Answers in Genesis | In English | → Christianity |
| AIH | Acoustical Imaging and Holography | In English | → Serial publications, periodicals → Acoustics |
| AIHA | American Italian Historical Association | In English | → Associations → History |
| AIIM | Association for Information and Image Management | In English | → Organizations and associations → Graphical processing → Knowledge management |
| AiInt | Air International | In English | → Serial publications, periodicals → Aeronautics, aircraft |
| AIJ | Activities Implemented Jointly | In English | |
| AIKE | Artificial and Knowledge Engineering Group | In English | → Artificial intelligence → Knowledge management |
| AIL | Avionics Integration Laboratories | In English | → Research institutes → Spaceflight engineering, astronautics |
| AILAS | Automatic Instrument Landing Approach System | In English | |
| AILS | Automatic Instrument Landing System | In English | |
| AILS | Ames Imaging Library Server | In English | → Graphical processing → Image processing |
| AILS | Agency for International Langage Study | In English | → Organizations and associations → Language, linguistics, literature |
| AIM | AOL Instant Messenger | In English | → Telecommunications |
| AIM | Automatic Information Management | In English | |
| AIM | Alternative Investment Market | In English | → Finance |
| AIME | American Institute Of Mechanical Engineers | In English | |
| AIMH | Association for Infant Mental Health | In English | → Associations → Psychiatry |
| AIMM | AGP Inline Memory Module | In English | |
| AIMSUN2 | Advanced Interactive Microscopic Simulator for Urban and Non-Urban Networks | In English | → Computer simulation → Transport and postal services |
| AIN | Austrian Institute of Navigation = ÖVN | Österreichischer Verein für Navigation | In German |
In English | → Geodesy, cartography → Vehicle engineering → Transport and postal services |
| AIOD | Ascent Insertion On-Orbit Deorbit | In English | |
| AIP | Aircraft Instrumented Payload | In English | |
| AIP | Avionics Integration Plan | In English | |
| AIP | Audiovisual Industry Promotion | In English | → Cinema, movies |
| AIPO | African Intellectual Property Organization = ARIPO | African Regional Industrial Property Organization | In English |
In English | → Organizations and associations → Industrial property → Artistic property |
| AIR | Action Item Report | In English | |
| AIR | Adaptive Intercommunication Requirement | In English | |
| AirCo | Air et Cosmos | In English | → Serial publications, periodicals → Astronomy → Aeronautics, aircraft → 6297 |
| AIRS | Atmospheric Infrared Sounder | In English | → Meteorology, climatology |
| AirSp | Air and Space | In English | → Serial publications, periodicals → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| AIS | Action Item Sheet | In English | |
| AIS | Airborne Imaging Spectrometer | In English | → Analytical chemistry |
| AIS | Airlock Illumination Subassembly | In English | |
| AIS | Analog-In Single-ended | In English | |
| AISA | Afghan Investment Support Agency | In English | → 33972 |
| AISC | American Institute of Steel Construction | In English | → Metallurgy |
| AISD | Autonetics ICBM Systems Division | In English | |
| AISI | American Iron And Steel Institute | In English | → Metallurgy |
| AIST | Abbreviated Integration System Test | In English | |
| AIST | Advanced Interferometric System Technology | In English | |
| AIST | Agency of Industrial Science and Technology | In English | → Research policy → Engineering, technology |
| AISTR | Advanced Interferometric System Technology Requirement | In English | |
| AIT | Autoignition Test | In English | |
| AIT | Advanced Intelligent Tape | In English | |
| AIU | Avionics Interface Unit | In English | → Human-computer interaction → Aeronautics, aircraft |
| AIU | Abort Interface Unit | In English | → Human-computer interaction |
| AIVC | Air Infiltration and Ventilation Centre | In English | → Environmental technology, water supply, waste management → Building |
| AIVET | Austrian Institute for Virtual Education Technique | In English | |
| AIVET | Austrian Institute for Virtual Education Techniques | In English | → Computer-based techniques → Education |
| AIXM | Aeronautical Information eXchange Model | In English | → Software → Aeronautics, aircraft |
| AJ | Astronomical Journal | In English | → Serial publications, periodicals → Astronomy |
| AJ | Art Journal | In English | → Serial publications, periodicals → Arts |
| AJ | Antijamming | In English | |
| AJ | Assembly Jig | In English | |
| AJA | American Journal of Archaeology (www.ajaonline.org) | In English | → Serial publications, periodicals → Archeology |
| AJAX | Asynchronous JavaScript And XML | In English | → Software |
| AJC | Ancient Jewish Coinage | In English | → Judaism → Economics |
| AJCh | Australian Journal of Chemistry | In English | → Serial publications, periodicals → Chemistry |
| AJCS | Automated Job Card System | In English | |
| AJHA | American Journalism Historians' Association | In English | → Associations → Newspapers, journalism → History |
| AJHS | American Jewish Historical Society | In English | → Organizations and associations → Judaism → History |
| AJPh | American Journal of Philology | In English | → Serial publications, periodicals → Philology |
| AJPIII | All Junky Pages Intentionally Illogical & Inconsistent | In English | → Networks, communication |
| AJS | American Journal of Sociology | In English | → Serial publications, periodicals → Sociology |
| AJSE | Arabian Journal of Science Engineering | In English | → Serial publications, periodicals → Mathematics and natural sciences → Applied sciences, technology |
| AJSR | Australian Journal of Soil Research | In English | → Serial publications, periodicals → 50 |
| AKA | Active Keel Actuator | In English | |
| AKC | American Kennel Club (www.akc.org) | In English | → Organizations and associations |
| AKM | Apogee Kick Motor | In English | |
| AL | Approach and Landing | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| AL | Autoland | In English | |
| Al | Aluminium = Al | Aluminium | In French = Al | Aluminium | In Afrikaans = Al | ألومنيوم | In Arabic = Al | Aluminiu | In Asturian = Al | Alüminium | In Azerbaijani = Al | অ্যালুমিনিয়াম | In Bengali = Al | Алюміній | In Belarusian = Al | Aluminijum | In Bosnian = Al | Aluminiom | In Breton = Al | Алуминий | In Bulgarian = Al | Alumini | In Catalan = Al | Алюмини | In Chuvash = Al | Hliník | In Czech = Al | Alluminiu | In Corsican = Al | Alwminiwm | In Welsh = Al | Aluminium | In Danish = Al | Aluminium | In German = Al | Alumiinium | In Estonian = Al | Αργίλιο | In Greek = Al | Aluminio | In Spanish = Al | Aluminio | In Esperanto = Al | Aluminio | In Basque = Al | آلومینیوم | In Persian = Al | Alumini | In Friulian = Al | Alúmanam | In Irish = Al | Ollymin | In Manx = Al | Almain | In Scottish Gaelic = Al | Aluminio | In Galician = Al | 알루미늄 | In Korean = Al | Ալյումին | In Armenian = Al | एलुमिनियम | In Armenian = Al | Aluminij | In Croatian = Al | Aluminio | In Ido = Al | Aluminium | In Indonesian = Al | Ál | In Icelandic = Al | Alluminio | In Italian = Al | אלומיניום | In Hebrew = Al | Alumunium | JV = Al | Aluminiu | In Kapampangan = Al | Alumini | In Swahili = Al | Aliminyòm | In Haitian Creole = Al | Bafûn | In Kurdish = Al | Aluminium | In Latin = Al | Alumīnijs | In Latvian = Al | Aluminium | In Letzeburgesh = Al | Aliuminis | In Lithuanian = Al | jinmrmalume | In Lojban = Al | Alumínium | In Hungarian = Al | Алуминиум | In Macedonian = Al | അലൂമിനിയം | In Malayalam = Al | ऍल्युमिनियम | In Marathi = Al | Aluminium | In Malay = Al | Хөнгөн цагаан | In Mongolian = Al | Aluminium | In Dutch = Al | アルミニウム | In Japanese = Al | Aluminium | In Norwegian = Al | Aluminium | In Nynorsk = Al | Aluminie | NOV = Al | Alumini | In Occitan = Al | Alyuminiy | In Uzbek = Al | Aluminium | In Low German = Al | Glin | In Polish = Al | Alumínio | In Portuguese = Al | Allu | In Kölsch = Al | Aluminiu | In Romanian = Al | Ch'aqu q'illay | In Quechua = Al | Алюминий | In Russian = Al | Alluminiu | In Sicilian = Al | Hliník | In Slovak = Al | Aluminij | In Slovenian = Al | Алуминијум | In Serbian = Al | Aluminijum | In Serbo-Croatian = Al | Alumiini | In Finnish = Al | Aluminium | In Swedish = Al | அலுமினியம் | In Tamil = Al | అల్యూమినియం | In Telugu = Al | อะลูมิเนียม | In Thai = Al | Nhôm | In Vietnamese = Al | Алюминий | In Tajik = Al | Alüminyum | In Turkish = Al | Алюміній | In Ukrainian = Al | Aluminiọmu | In Yoruba = Al | 铝 | In Chinese |
In English | → Chemistry |
| ALA | American Library Association | In English | → Associations → Libraries |
| ALAE | Atmospheric Lyman-Alpha Emissions | In English | → Meteorology, climatology |
| ALARA | As Low As Reasonably Achievable | In English | → Nuclear technology |
| ALAS | Approach/Landing Autopilot Subsystem | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| ALASAT | Air-Launched Antisatellite | In English | → Military engineering → Spaceflight engineering, astronautics |
| ALASS | Alternate Low-Altitude Surveillance System | In English | |
| ALB | Acceptance Log Book | In English | |
| ALC | Aft Load Controller | In English | |
| ALC | Air Logistics Center | In English | → Maintenance and logistics → Transport and postal services |
| ALC | Audio Load Compensator | In English | |
| ALC | Automatic Level Control | In English | |
| ALC | Automatic Light Control | In English | |
| ALCA | Automatic Level-Control Assembly | In English | |
| ALCA | Aft Load Controller Assembly | In English | |
| ALCC | Airborne Launch Control Center | In English | |
| ALCM | Air-Launched Cruise Missile | In English | → Military engineering → Aeronautics, aircraft |
| ALCOA | Aluminum Corporation Of America | In English | → Metallurgy |
| ALCOM | Algorithm Line-Of-Sight Comparison | In English | |
| ALCOM | Aquaculture for Local Community Development Programme | In English | → Agricultural sciences |
| ALD | Association of Lighting Designers | In English | → Associations |
| ALDC | Automatic Load and Drive Control | In English | |
| ALDO | Activity-Level-Dependent Operation | In English | |
| ALDP | Advanced Launch Development Program | In English | → Spaceflight engineering, astronautics |
| ALE | Airport Lighting Equipment | In English | |
| ALE | Airborne Laser Experiment | In English | |
| ALERT | Acute Launch Emergency Reliability Tip | In English | |
| ALERT | Acute Launch Emergency Restraint Tip | In English | |
| ALF | Animal Liberation Front | In English | → International relations → Environment, environmental sciences |
| ALFA | Air-Lubricated Free Attitude | In English | |
| ALFT | Approach and Landing Flight Test | In English |