| Abbreviation | Definition |
|---|---|
| TYP | Typical |
| TZ | Test Zone |
| TZ | Translation Hand Controller Z-Axis Direction |
| TZO | Thorne-Zytkow Object |
| U | Underfloor |
| U | Uranium |
| U/C | Under Current |
| U/D | Update |
| U/L | Uplink |
| U/L | Uplink (UPLK preferred) |
| U/M | Unit of Measure |
| U/M | Unmanned |
| U/M | Unscheduled Maintenance |
| U/O | Used on |
| U/S | Upper Stage |
| U/S | Upstream |
| U/V | Under Voltage |
| U/W | Used with |
| UA | Microampere |
| UAB | University of Alabama at Birmingham |