| AAD | Access to Archival Databases |
| AAT | Arc Attribute Table |
| ABC | Alphabetically Based Computerized |
| ABT | Analytical Base Table |
| ABVD | Austronesian Basic Vocabulary Database |
| AC | Additional Content |
| ACB | Application Control Block |
| ACC | Attribute Collection Context |
| ACDB | Automated Cost Data Base |
| ACDC | Accurate Coordinate Datasets Collection |
| ACDS | Appeals Centralized Database System |
| ACF | Advanced Computer Feasability |
| ACID | Automatic Consistency Integration Of Database |
| ACID | Atomic, Consistent, Independent, and Durable |
| ACM | Agglomeration Coarse Matrix |
| ACMRU | Auto Complete Most Recently Used |
| ACP | Admin Control Panel |
| ACPN | Asymptotic Continuous Petri Net |
| ACSD | Adult Cardiac Surgery Database |
| ACT | Advanced Computer Technologies |