| Abbreviation | Definition |
|---|---|
| ABF | Adobe Binary Screen Font |
| ABK | Avigo Backup file |
| ABK | CorelDraw Automatic BacKup |
| ABM | PhotoPlus Album file |
| ABR | Adobe PhotoShop BRush file |
| ABS | Abscissa Data file |
| ABS | Abstracts (info file) |
| AC$ | Spooled plot file (AutoCAD AutoSpool) |
| ACA | Project Manager Workbench Project file |
| ACAD | AutoCAD database file |
| ACB | ACB Compressed file archive |
| ACB | Graphics (ACMB) |
| ACC | Program (DR-DOS - ViewMax) (GEM / resident) |
| ACCDB | Access 2007/2010 Database file |
| ACE | ACE or WinACE Compressed file archive |
| ACF | Adobe PhotoShop Custom Filter |
| ACFM | Adobe Composite Font Metrics file |
| ACGI | ACGI Script (WWW) |
| ACL | Corel Draw 6 Keyboard Accelerator |
| ACL | Microsoft Office Auto-Correct List |