| Abbreviation | Definition |
|---|---|
| UIQ | Urinary Impact Questionnaire |
| UJL | Upper Jaw Length |
| UK | Unknown |
| UKV | Potassium Excretion rate |
| UL | Upper Lobe |
| ULN | Ulnar |
| ULO | Ultra Low Oxygen |
| ULOQ | Upper left outer quadrant |
| ULQ | Upper left quadrant |
| ULR | Universal Leukocyte Reduction |
| UMB | UMBilicus |
| UMB | Umbilicus (navel) |
| UMDC | University of Michigan Depression Center |
| UMG | Ultimate Memory Guide |
| UML | Upper Motor Lesion |
| UMLSKS | Unified Medical Language System Knowledge Source Server |
| UMN | Upper Motor Neuron |
| UMNL | Upper motor neuron lesion |
| UN | Ulnar nerve |
| UN | Unlimited Nervousness |