| Acronym | Meaning |
| AML | ARC Macro Language |
| AML | Acute Myeloid Leukemia |
| AMLCD | Active Matrix Liquid Crystal Display |
| AMMA | Acrylonitrile-methyl Methacrylate Copolymer |
| AMMRC | Army Materials And Mechanics Research Center |
| AMN | Alkali Metal Nitrite(s) |
| AMNH | American Museum Of Natural History |
| AMO | Alternant Molecular Orbital |
| AMO MT | Alternant Molecular Orbital Matsubara-Toyozawa Method |
| AMORS | Atomic Magnetooptic Resonance Spectroscopy |
| AMOS | Australian Meteorological And Oceanographic Society |
| AMOS | Automated Meteorological Observing System |
| AMOS | Air Management Oversight System |
| AMOSC | Australian Marine Oil Spill Center |
| AMP | Adenosine 5'-monophosphate |
| AMPA | Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid |
| AMPD | 2-amino-2-methyl 1 |
| AMPD | AMP Deaminase |
| AMPK | AMP-activated Protein Kinase |
| AMPS | 2-acrylamido-2-methylpropanesulfonic Acid [15214-89-8] |
| AMPS | Airborne Multisensor Pod System |
| AMPTE | Active Magnetosphere Particle Tracer Explorers |
| AMR | Anisotropic Magnetoresistance |
| AMRIR | Advanced Medium Resolution Imaging Radiometer |
| AMS | AIRS Area/Mobile Source Subsystem (subsystem Of AIRS) |
| AMS | Alpha Magnetic Spectrometer |
| AMS | American Mathematical Society |
| AMS | Accelerator Mass Spectrometry |
| AMS | Accelerator Mass Spectrometry Or Spectroscopy |
| AMS | Aerospace Material Specification |
| AMS | Alpha Methyl Styrene |
| AMSA | Association Of Metropolitan Sewerage Agencies |
| AMSR | Advanced Microwave Scanning Radiometer |
| AMSU | Advanced Microwave Sounding Unit |
| AMT | Audio-magneto-telluric Method |
| AMTEC | Alkali Metal Thermoelectric Converter |
| AMTIC | Ambient Monitoring Technology Information Center |
| AMTIR | Amorphous Material Transmitting Infrared Radiation |
| AMTS | Advanced Moisture And Temperature Sounder |
| AMU | Atomic Mass Unit |
| AMV | Alfalfa Mosaic Virus |
| AMV | Avian Myeloblastosis Virus |
| AMWA | American Metropolitan Water Association |
| ANA | Atm. Mesoscale Numerical Pollution Model |
| ANA | Adiabatic Nuclei Approximation (in Electron-mol. Scattering) |
| ANA | Antinuclear Antibodies |
| ANADA | Abbreviated New Animal Drug Application |
| ANATEX | Across North America Tracer Experiment |
| ANC | Acid Neutralizing Capacity |
| ANCA | Anti-neutrophil Cytoplasmic Antibodies |