| Abbreviation | Definition |
|---|---|
| Asst | Assistant |
| ASS'T | Assistant |
| AST | Advanced Skills Teacher |
| AST | Automotive Service Technician |
| ASU | Accident Sickness and Unemployment |
| AT | Administration Technician |
| ATALL | After Ken; 1818 |
| ATC | Afghan Technical Consultant |
| ATC | Air Traffic Controller |
| ATCG | Annual Total Compensation Guarantee |
| ATCS | Air Traffic Control Specialist |
| ATM | Adobe Type Manager |
| ATP | Air Transport Pilot |
| ATR | Art Therapist Registered |
| ATTITUDE | Any Time Taking Initiative Towards Updating Developing Excellence |
| AUSA | Assistant United States Attorney |
| AUST | Assistant United States Trustee |
| AV | Annual Vacation |
| AVA | Amateur Voice Actor |
| AVID | Advancement Via Individual Determination |