| Abbreviation | Definition |
|---|---|
| U | Unclassified |
| U | Unidentified |
| U | Unit |
| U | Unknown |
| U | Unmodified |
| U | Unreliable |
| U | Unterseeboot |
| U | Uphill |
| U | Wind Speed |
| U.S.AFRICOM | United States Africa Command |
| U/C | Unit Cost |
| U/C | Upconverter |
| U/F | Unit of Fire |
| UA | UnAuthorized |
| UA | Unauthorized Absence |
| UA | Unconditional Annihilation |
| UA | Underground Access |
| UA | Underground Area |
| UA | Unit Administration |
| UA | Unit Attack |