| Abbreviation | Definition |
|---|---|
| AMM | Add Mayo and Mustard |
| AMPA | Annual Meeting of the Provincial Assembly |
| AND | Logical AND |
| ANWA | All Nations Worship Assembly |
| AOI | And Or Invert |
| AP | Allocation Pointer |
| APAS | Androgynous Peripheral Assembly System |
| APC | Asynchronous Procedure Call |
| AQCB | Assembly of Quebec Catholic Bishops |
| AR | Add Rows |
| AR | Address Register |
| ARB | Aij Request Block |
| ARCAM | Legislative Assembly of Cameroon |
| ARIBA | Antimicrobial Resistance Identification By Assembly |
| ARMA | Accumulator Reservoir Manifold Assembly |
| ARPL | Adjust Requested Privilege Level |
| AS | Add Sideways |
| ASAP | Assisted Solar Assembly Program |
| ASC | Additional Sense Code |
| ASF | Aspect Source Flag |