| Abbreviation | Definition |
|---|---|
| US | United States |
| USA | United States of A**holes |
| USA | United States of Awesome |
| USAA | United States Army Audit |
| USAAAD | United States Army Air Ambulance Detachment |
| USAAC | United States Army Accessions Command |
| USAAF | United States Advanced Aviation Force |
| USAAS | United States Army Air Service |
| USAAS | United States Army Ambulance Service |
| USAB | United States Amateur Basketball |
| USAB | United States Army Berlin |
| USAB | United States of American Business |
| USAC | United States Army Cadet |
| USAC | United States Auto Club |
| USACA | United States of America Cricket Association |
| USACE | United States Army Corps of Engineers |
| USACIL | United States Army Criminal Investigation Laboratory |
| USACO | United States of America Computing Olympiad |
| USAD | United States Academic Decathlon |
| USAF | United States Air Force |