| Abbreviation | Definition |
|---|---|
| UMT | Unit Of Medical Time |
| UNF | Unified National Fine |
| UOB | Units Of Behavior |
| UOI | Unit Of Interchange |
| UOM | Unit Of Measure |
| UOW | Unit Of Work |
| UPH | Unit Per Hour |
| UPH | Unit Per Hours |
| UPH | Units Per Hour |
| UPS | Updates Per Second |
| UR | Unit Resolution |
| USC | United States Customary |
| USCU | United States Customary Units |
| USF | Usable Square Footage |
| USG | United States gallon (liquid = 231 cu. in. = 3.785411784 litres; dry = 268.8025 cu. in. or 4.40488377086 litres) |
| USMB | United States Metric Board |
| USMN | Unified Spatial Metrology Network |
| UT | Unit of Time |
| UTAP | Universal Trail Assessment Process |
| UU | Unique Unit |