| Abbreviation | Definition |
|---|---|
| UDP | Umpire Development Program |
| UDR | Undergraduate Departmental Representative |
| UDT | Upper Division Transfer |
| UE | Undoubted Excellence |
| UE | University Executive |
| UES | United Engineering Society |
| UFI | Ultra Flight Instructor |
| UFM | Underwater Fan Mechanic |
| UG | Underground Guard |
| UGM | Usenet Group Mentor |
| UH | Unlikely Hero |
| UI | Unemployment Insurance |
| UIC | Umpire In Chief |
| UIC | Unemployment Insurance Of Canada |
| UIF | Unemployment Insurance Fund |
| UIR | UROP In Residence |
| UIS | University Indentured Servant |
| UIT | Unusually Inquisitive Trainee |
| UIW | Universal (Mechanical) Iron Worker |
| UJM | Utah Job Match |