| Abbreviation | Definition |
|---|---|
| USF | Upstream Stimulatory Factor |
| USFWS | United States Fish and Wildlife Service |
| USGS | United States Geological Survey |
| USIA | United States Information Agency |
| USIGS | United States Imagery and Geospatial System |
| USIS | United States Information Service |
| USNODC | United States National Oceanographic Data Center |
| USNS | United States Naval Ship |
| USNV | United States Naval Vessel |
| USO | Unidentified Sunken Object |
| USRD | Underwater Science, Research & Development, Inc. |
| USRD | Underwater Sound Reference Division, Naval Undersea Warfare Center |
| USRP | Urban Streams Restoration Program |
| USRU | Underwater Search and Rescue Unit |
| USRW | Upper Suwannee River Watershed |
| USW | UnderSea Warfare |
| UT | Undersea Technologies |
| UTC | Coordinated Universal Time (Temps Universel Coordonné) |
| UTC | Coordinated Universal Time (Temps Universel Coordonné) [language-independent abbreviation, French: BIPM-verified] |
| UTS | Under The Sea |