| Abbreviation | Definition |
|---|---|
| ACIU | Allied Central Interpretation Unit |
| ACIU | Attitude Control Interface Unit |
| ACIW | Anderson Custom Iron Works |
| ACJ | Airbus corporate jet |
| ACJ | Alexander Christiaan Jacob |
| ACJ | Automatic Cold Junction |
| ACJA | Arizona Code of Judicial Administration |
| ACJCS | Assistant to the Chairman Joint Chiefs of Staff |
| ACJD | Angel City Junior Derby |
| ACJL | Administration Of Criminal Justice Law |
| ACJL | Auto Craft Japan Ltd |
| ACJR | Ashtabula Carson and Jefferson Railroad |
| ACJU | All Ceylon Jamiathul Ulema |
| ACJU | All Ceylon Jamiyathul Ulama |
| ACJU | All Ceylon Jamiyyathul Ulama |
| ACJU | All Ceylon Jammiyathul Ulama |
| ACK | Adventurer Conqueror King |
| ACK | Akademickie Cenrum Kariery |
| ACK | Amsterdam Compiler Kit |
| ACK | Arrogant Crappy Krap |