| A&C | Abatement & Control | - | Business and Finance |
| A&R | Air And Radiation | - | Business and Finance |
| A/C | Aircraft | - | Business and Finance |
| A/C | Air Conditioning | - | Business and Finance |
| A/D | Analog-to-digital | - | Business and Finance |
| A/H | Air Handling | - | Business and Finance |
| A/I | Accident/incident | - | Business and Finance |
| AA | Access Authorization | - | Business and Finance |
| AA | Accountable/activity Area | - | Business and Finance |
| AA | Activity Area | - | Business and Finance |
| AA | Adverse Action | - | Business and Finance |
| AA | Affirmative Action | - | Business and Finance |
| AA | Assistant Administrator | - | Business and Finance |
| AA/EEO | Affirmative Action/equal Employment Opportunity | - | Business and Finance |
| AAA | American Arbitration Association | - | Business and Finance |
| AAAS | American Association For The Advancement Of Science | - | Business and Finance |
| AACR | Angle-American Cataloging Rules | - | Business and Finance |
| AACS | Airborne Activity Confinement System | - | Business and Finance |
| AADT | Average Annual Weekday Traffic | - | Business and Finance |
| AAEE | American Academy Of Environmental Engineers | - | Business and Finance |
| AAG | Association Of American Geographers | - | Business and Finance |
| AAH | Advanced Attack Helicopter | - | Business and Finance |
| AALC | Amphibious Assault Landing Craft | - | Business and Finance |
| AAM | Airborne Activity Monitor | - | Business and Finance |
| AAM | Air-to-air Missile | - | Business and Finance |
| AAOE | Airborne Antarctic Ozone Experiment | - | Business and Finance |
| AAP | Aviation Applications Program | - | Business and Finance |
| AAP | Atmospheric Analysis And Prediction Division | - | Business and Finance |
| AAP | Affirmative Action Program | - | Business and Finance |
| AAP | Asbestos Action Program | - | Business and Finance |
| AAR | Affirmative Action Representative | - | Business and Finance |
| AARADCOM | US Army Armanents R&D Command | - | Business and Finance |
| AARC | Alliance For Acid Rain Control | - | Business and Finance |
| AARP | American Association Of Retired People | - | Business and Finance |
| AAS | American Astronomical Society | - | Business and Finance |
| AAS | Acid Addition System | - | Business and Finance |
| AAS | Atomic Absorption Spectroscopy | - | Business and Finance |
| AASE | Airborne Arctic Stratospheric Expedition | - | Business and Finance |
| AASM | Advanced Air To Surface Missile | - | Business and Finance |
| AASO | Army Aeronautical Service Office | - | Business and Finance |
| AAW | Antiair Warfare | - | Business and Finance |
| AB | Architect Building | - | Business and Finance |
| ABA | American Bar Association | - | Business and Finance |
| ABAQUS | Finite-element Computer Code | - | Business and Finance |
| ABB | Asea Brown Boveri | - | Business and Finance |
| ABC | Aerobiochemical | - | Business and Finance |
| ABC | Accelerator-based Conversion | - | Business and Finance |
| ABC | Advanced Ball Concept | - | Business and Finance |
| ABE | Army Background Experiment | - | Business and Finance |
| ABES | Alliance For Balanced Environmental Solutions | - | Business and Finance |
| ABFEL | Air-based Free-electron Laser | - | Business and Finance |
| ABHX | Air Blast Heat Exchanger | - | Business and Finance |
| ABL | Airborne Laser | - | Business and Finance |
| ABL | Atmospheric Boundary Layer | - | Business and Finance |
| ABLE | Activity Balance Line Evaluation | - | Business and Finance |
| ABLE | Amazon Boundary Layer Experiment | - | Business and Finance |
| ABLE-2B | Arctic/Atlantic/Atmospheric Boundary Layer Experiment | - | Business and Finance |
| ABM | Antiballistic Missile | - | Business and Finance |
| ABRES | Advanced Ballistic Re-entry System | - | Business and Finance |
| ABRV | Advanced Ballistic Re-entry Vehicle | - | Business and Finance |
| ABS | Automatic Backup Shutdown | - | Business and Finance |
| ABS-SC | Automatic Backup Shutdown Of Safety Computer | - | Business and Finance |
| ABTRES | Abatement & Residual Forecasting Model | - | Business and Finance |
| ABV | Auxiliary Building Ventilation | - | Business and Finance |
| ABWA | American Business Women's Association | - | Business and Finance |
| AC | Alternating Current | - | Business and Finance |
| AC | Adirondac Conference | - | Business and Finance |
| AC | Actual Commitment | - | Business and Finance |
| AC | Advisory Circular/committee | - | Business and Finance |
| AC | Alternating Current | - | Business and Finance |
| AC | Ancho Canyon | - | Business and Finance |
| AC | Area Coordinator | - | Business and Finance |
| ACA | Atmospheric Chemistry Of Aerosols | - | Business and Finance |
| ACA | American Conservation Association | - | Business and Finance |
| ACA | Applied Combinatorial Analysis | - | Business and Finance |
| ACACIA | A Consortium For The Application Of Climate Impact Assessments | - | Business and Finance |
| ACAP (ACAPS) | Advanced Computer For Array Processing | - | Business and Finance |
| ACARS | ARINC Communications And Relay System | - | Business and Finance |
| ACARS | ARINC Communication | - | Business and Finance |
| ACAS | Advisory Committee For Atmospheric Sciences | - | Business and Finance |
| ACATS | Airborne Chromatograph For Atmospheric Trace Species | - | Business and Finance |
| ACB | Air-operated Circuit Breaker | - | Business and Finance |
| ACBM | Asbestos-containing Building Material | - | Business and Finance |
| ACC | Abnormal Condition Control | - | Business and Finance |
| ACC | Abrupt Climate Change | - | Business and Finance |
| ACC | Antarctic Circumpolar Current | - | Business and Finance |
| ACC | Accumulator | - | Business and Finance |
| ACCD | Aircraft Compatibility Control Drawing | - | Business and Finance |
| ACCENT | Atmospheric Chemistry Of Combustion Emissions Near The Tropopause | - | Business and Finance |
| ACD | Atmospheric Chemistry Division | - | Business and Finance |
| ACD | Advanced Conceptual Design | - | Business and Finance |
| ACDA | Arms Control And Disarmament Agency | - | Business and Finance |
| ACDAR | Acoustic Radar | - | Business and Finance |
| ACDF | Advanced Chemical Diagnostics Facility | - | Business and Finance |
| ACDWG | Atmospheric Center Of Data Working Group | - | Business and Finance |
| ACE | Alliance For Clean Energy | - | Business and Finance |
| ACE | American Council On Education | - | Business and Finance |
| ACE | Antarctic Current Experiment | - | Business and Finance |
| ACE | Aerosol Characteristics Experiment | - | Business and Finance |
| ACE | Accelerated Computing Environment | - | Business and Finance |
