| Acronym | Meaning |
| AESOP | Automated Electronic System For Ocean Pollution |
| AESOP | Ab-initio Effective Spin-orbit Operator |
| AESOPS | Antarctic Environment Southern Ocean Process Study |
| AET | S-(2-aminoethyl)isothiouronium Bromide Hydrobromide |
| AET | Apparent Effects Thresholds |
| AET | Acoustic Emission Technique |
| AETE | Absorption-energy Transfer-emission |
| AETM | Analytical Electron Transmission Microscopy |
| AEVO | Active Electron Virtual Orbital |
| AEY | Auger Electron Yield |
| AEZ | Alkaline Earth Zeolite |
| AF | Alternating Field Demagnetization |
| AF | Anaerobic Filter |
| AF | Atomic Fluorescence |
| AF | Audio Frequency |
| AFA | Abstract Factor Anal. (statistics) |
| AFA | Average Fock Approxn. |
| AFB | Anaerobic Fluidized Bed |
| AFB | Atmospheric Fluidized Bed |
| AFBBR | Anaerobic Fluidized Bed Biofilm Reactor |
| AFBC | Atmospheric Fluidized Bed Combustion |
| AFBR | Anaerobic Fluidized-bed Reactor |
| AFBS | Anaerobic Fluidized Bed Systems |
| AFC | Assimilation (with) Fractional Crystallization (geochemistry) |
| AFC | Antibody Forming Cell |
| AFC | Automatic Frequency Control |
| AFCEE | Air Force Center For Environmental Excellence |
| AFCOP | Active Filler-controlled Pyrolysis |
| AFCRL | Air Force Cambridge Research Laboratories |
| AFCS | Alliance For Cellular Signaling |
| AFD | Automated Forging Design |
| AFDM | Ash Free Dry Mass |
| AFEAS | Alternative Fluorocarbon Environmental Acceptability Study |
| AFF | Aberration Free Focus |
| AFFF | Aqueous Film-forming Foam |
| AFFTC | Air Force Flight Test Center |
| AFGF | Acidic Fibroblast Growth Factor |
| AFGL | Air Force Geophysics Laboratory |
| AFGP | Antifreeze Glycoprotein |
| AFID | Alkali Flame Ionization Detector |
| AFIS | Advanced Fiber Information System |
| AFIS | Automated Fingerprint Identification System |
| AFLP | Amplified Fragment Length Polymorphism |
| AFM | Abrasive Flow Machining |
| AFM | Atomic Force Microscopy |
| AFMMP | Advanced Field Monitoring Methods Program |
| AFMR | American Federation Of Medical Research |
| AFMR | Antiferromagnetic Resonance |
| AFNOR | Association Francaise De Normalisation (Paris |
| AFOE | Advanced Fiber Optic Echelle Spectrometer |