| Abbreviation | Definition |
|---|---|
| ACI | Access Control Interface |
| ACI | Assign Call Inhibit |
| ACIS | Access Control Interlock System |
| ACK | ACKnowledge |
| ACL | Access Control List |
| ACL | Agent Communication Language |
| ACL | Asynchronous connectionless Link |
| ACM | Abstract Control Model |
| ACM | Asynchronous Communication Method |
| ACN | Advanced Control Network |
| ACNG | Austin Christian Networking Group |
| ACNS | Application and Content Networking System |
| ACNS | Applied Cryptography and Network Security |
| ACNT | Advanced Computer and Networking Technology |
| ACNT | Advanced Computer Networking Technology |
| ACON | Asian Community Online Network |
| ACPN | Art, Comedy, & Pop-Culture Network |
| ACPN | Australia China Property Network |
| ACRQ | Alternate Conditional Request Queue |
| ACS | ADSL Caching Server |