| Abbreviation | Definition |
|---|---|
| A | Archived |
| AA | ASCII Art |
| AAA | Authentication Authorisation and Accounting |
| AAA | Automatic Artwork Alignment |
| AAAF | ATRACC ATM Added Functions |
| AABB | Axis Aligned Bounding Box |
| AAC | Augmentative and Assistive Computing |
| AACE | Austin Atari Computer Enthusiasts |
| AACS | Advanced Access Content System |
| AACTS | APS Automated Client Tracking System |
| AAF | Advanced Authoring Format |
| AAG | Assistant Adjutant General |
| AAHC | American Association for History and Computing |
| AAI | Animal Artificial Intelligence |
| AAIP | Arbitrary Attribute Interchange Protocol |
| AAIS | Automated Acquisition Information System |
| AAL5 | ATM Adaptation Layer 5 |
| AAOCC | Accuracy Authority Objectivity Currency And Coverage |
| AB | Application Bulletin |
| ABC | Abstract Base Class |