| A.I. | Active Ingredient | - | Computer Acronyms(common) |
| A/C | Activated Carbon | - | Computer Acronyms(common) |
| A/CNK | [Al2O3/(CaO + Na2O + K2O)] (Shand's Index) | - | Computer Acronyms(common) |
| A/PI | Ab Initio Perturbed Ion (quantum Clacn. Method) | - | Computer Acronyms(common) |
| A2LA | American Association For Laboratory Accreditation | - | Computer Acronyms(common) |
| AA | Aluminum Association | - | Computer Acronyms(common) |
| AA | Assistance Administration | - | Computer Acronyms(common) |
| AA | Assistant Administrator | - | Computer Acronyms(common) |
| AA | Activation Analysis | - | Computer Acronyms(common) |
| AA | Atomic Absorption | - | Computer Acronyms(common) |
| AAA | Abdominal Aortic Aneurysm | - | Computer Acronyms(common) |
| AAAI | American Association For Artificial Intelligence | - | Computer Acronyms(common) |
| AAAS | American Academy Of Arts And Sciences | - | Computer Acronyms(common) |
| AAAS | American Association For The Advancement Of Science | - | Computer Acronyms(common) |
| AABW | Antarctic Bottom Water | - | Computer Acronyms(common) |
| AACA | Ambient Atmosphere Conditions And Aging | - | Computer Acronyms(common) |
| AACC | American Association For Clinical Chemistry | - | Computer Acronyms(common) |
| AACC | American Association Of Cereal Chemists | - | Computer Acronyms(common) |
| AACE | American Association Of Coast Engineers | - | Computer Acronyms(common) |
| AACG | American Association For Crystal Growth | - | Computer Acronyms(common) |
| AACI | Association Of American Cancer Institutes | - | Computer Acronyms(common) |
| AACR | American Association For Cancer Research | - | Computer Acronyms(common) |
| AACVD | Aerosol-assisted Chemical Vapor Deposition | - | Computer Acronyms(common) |
| AAD | Atomic Absorption Detector | - | Computer Acronyms(common) |
| AADA | Abbreviated Antibiotic Drug Application | - | Computer Acronyms(common) |
| AADO | Angular (momentum Conservation) Average Dipole Orientation Theory (in Io-mol. Reactions) | - | Computer Acronyms(common) |
| AAEC | Australian Atomic Energy Commission | - | Computer Acronyms(common) |
| AAEE | American Academy Of Environmental Engineers | - | Computer Acronyms(common) |
| AAEM | Advanced Analytical Electron Microscope | - | Computer Acronyms(common) |
| AAETA | Atomic Spectroscopy With Electrothermal Atomization | - | Computer Acronyms(common) |
| AAFEB | Anaerobic Attached Film Expanded Bed | - | Computer Acronyms(common) |
| AAFEGE | Asymptotically Adjusted Free-electron-gas Exchange (potential) | - | Computer Acronyms(common) |
| AAGP | Aerobic Attached Growth Process | - | Computer Acronyms(common) |
| AAHIS | Advanced Airborne Hyperspectral Imaging System | - | Computer Acronyms(common) |
| AAI | American Association Of Immunologists | - | Computer Acronyms(common) |
| AAIP | American Association Of Investigative Pathologists | - | Computer Acronyms(common) |
| AAIT | Atomic Absorption Inhibition Titration | - | Computer Acronyms(common) |
| AAIW | Antarctic Intermediate Water | - | Computer Acronyms(common) |
| AAL | Acceptable Ambient Level(s) | - | Computer Acronyms(common) |
| AALA | American Association For Laboratory Accreditation | - | Computer Acronyms(common) |
| AAM | Automated Auger Microprobe | - | Computer Acronyms(common) |
| AAMI | Association For The Advancement Of Medical Instrumentation | - | Computer Acronyms(common) |
| AAMOM | An Approximate Molecular Orbital Method | - | Computer Acronyms(common) |
| AAO | Acetaldehyde Oxime | - | Computer Acronyms(common) |
| AAO | Amino Acid Oxidase | - | Computer Acronyms(common) |
| AAODL | Atmospheric Aerosols And Optics Data Library | - | Computer Acronyms(common) |
| AAOE | Airborne Antarctic Ozone Experiment | - | Computer Acronyms(common) |
| AAOM | American Academy Of Occupational Medicine | - | Computer Acronyms(common) |
| AAP | Asbestos Action Program | - | Computer Acronyms(common) |
| AAPCO | Association For American Pesticide Control Officials | - | Computer Acronyms(common) |
| AAPDI | Anisotropic Atom Point Dipole | - | Computer Acronyms(common) |
| AAPG | American Association Of Petroleum Geologists | - | Computer Acronyms(common) |
| AAPM | American Association Of Physicists In Medicine | - | Computer Acronyms(common) |
| AAPS | American Association Of Pharmaceutical Scientists | - | Computer Acronyms(common) |
| AAQS | Ambient Air Quality Standard (USEPA) | - | Computer Acronyms(common) |
| AAR | Association Of American Railroads | - | Computer Acronyms(common) |
| AAR | Accumulation-area Ratio (for Glaciers) | - | Computer Acronyms(common) |
| AAR | Alkali-aggregate Reaction | - | Computer Acronyms(common) |
| AARC | Alliance For Acid Rain Control | - | Computer Acronyms(common) |
| AAS | Atomic Absorption Spectroscopy | - | Computer Acronyms(common) |
| AASD | Anaerobic Activated Sludge Digestion | - | Computer Acronyms(common) |
| AASE | Airborne Arctic Stratospheric Expedition | - | Computer Acronyms(common) |
| AASHO | American Association Of State Highway Officials | - | Computer Acronyms(common) |
| AASHTO | American Association Of State And Highway Transportation Officials | - | Computer Acronyms(common) |
| AASIR | Advanced Atmospheric Sounding And Imaging Radiometer | - | Computer Acronyms(common) |
| AAT | Aspartate Aminotransferase | - | Computer Acronyms(common) |
| AAT | Atomic Axial Tensor (in Mol. Optical Properties Calcns.) | - | Computer Acronyms(common) |
| AATB | American Association Of Tissue Banks | - | Computer Acronyms(common) |
| AATCC | American Association Of Textile Chemists And Colorists | - | Computer Acronyms(common) |
| AATSR | Advanced Along-Track Scanning Radiometer | - | Computer Acronyms(common) |
| AAU | Amendment To Allege Use | - | Computer Acronyms(common) |
| AAV | Adeno-associated Virus | - | Computer Acronyms(common) |
| AAW | Air Acetylene Welding | - | Computer Acronyms(common) |
| AB | Arc Brazing | - | Computer Acronyms(common) |
| ABA | Abscisic Acid | - | Computer Acronyms(common) |
| ABA | Acid-base Account [related To Acid-forming Potential] | - | Computer Acronyms(common) |
| ABA | Acrylonitrile-butadiene Acrylate | - | Computer Acronyms(common) |
| ABAE | Adult Bovine Aortic Endothelial | - | Computer Acronyms(common) |
| ABBOT | Atomic Billiard Ball Orbital Theory | - | Computer Acronyms(common) |
| ABC | ATP-binding Cassette | - | Computer Acronyms(common) |
| ABC | Absorbing Boundary Condition (green Function) | - | Computer Acronyms(common) |
| ABC | Avidin-biotin Complex | - | Computer Acronyms(common) |
| ABCM | Assembly (of) Boundary-controlled Monolayers (method For Electronic-structure Calcns.) | - | Computer Acronyms(common) |
| ABEP | Acetate Buffer Extraction Procedure | - | Computer Acronyms(common) |
| ABES | Alliance For Balanced Environmental Solutions | - | Computer Acronyms(common) |
| ABET | Accreditation Board For Engineering And Technology | - | Computer Acronyms(common) |
| ABF | Activated Biofilter | - | Computer Acronyms(common) |
| ABG | Arterial Blood Gas | - | Computer Acronyms(common) |
| ABHP | American Board Of Health Physics | - | Computer Acronyms(common) |
| ABI | Automated Ball Indentation | - | Computer Acronyms(common) |
| ABIH | American Board Of Industrial Hygienists | - | Computer Acronyms(common) |
| ABL | Atmospheric Boundary Layer | - | Computer Acronyms(common) |
| ABLE | Amazon Boundary Layer Experiment | - | Computer Acronyms(common) |
| ABLE | Arctic Boundary Layer Expedition | - | Computer Acronyms(common) |
| ABLE | Atmospheric Boundary Layer Experiments | - | Computer Acronyms(common) |
| ABMA | American Boiler Manufacturers Association | - | Computer Acronyms(common) |
| ABMR | Atomic Beam Magnetic Resonance | - | Computer Acronyms(common) |
| ABMT | Autologous Bone Marrow Transplantation | - | Computer Acronyms(common) |
| ABO | Adiabatic Born-Oppenheimer (wave Functions) | - | Computer Acronyms(common) |
| ABO | Antibonding Bond Orbital | - | Computer Acronyms(common) |
