| Accelerated Graphics Port | ActiveX |
| Adobe Illustrator | Adobe Photoshop |
| Advanced Research Projects Agency Network | Advanced Technology Attachment |
| Adware | Adware Networks |
| AFK | Alias |
| American Standard Code for Information Interchange | Anchor |
| Anonymous FTP | API |
| Applet | Application |
| Application Programming Interface | Application Protection |
| ASAP | Ascii File |
| Authentication | Avatar |
