- U -
| Abbreviation | Meaning |
|---|---|
| U | University |
| UATC | University Air Training Corps |
| UATCS | University Air Training Corps Squadrons |
| UC | United Kingdom-Caribbean convoy |
| UCC | United Church of Canada |
| UD | University Detachments |
| UG | United States-Gibraltar convoy |
| UIC | Unit Identification Code |
| UK | United Kingdom |
| UKALM | United Kingdom Air Liaison Mission |
| UKAR | United Kingdom Approach Routes |
| UKCC | United Kingdom Commercial Corporation |
| UKSA | United Kingdom Shipping Adviser |
| UL | Unattached List |
| ULNDHQ(D) | Unattached List National Defence Headquarters (Details) |
| ULO | University Liaison Officer |
| UMHRCAMC | Utopia Military Hospital, Royal Canadian Army Medical Corps |
| UMS | Unit Medical Section |
| UMSP | Undergraduate Medical Subsidization Plan |
| UNAL | Unallotted |
| UNDOF | United Nations Disengagement Observer Force (Golan Heights) |
| UNEFME | United Nations Emergency Force Middle East |
| UNFICYP | United Nations Force in Cyprus |
| UNIFIL | United Nations Interim Force in Lebanon |
| UNIPOM | United Nations India Pakistan Observation Mission |
| Univ | University |
| unk | unknown |
| UNMOGIP | United Nations Military Observation Group in India and Pakistan |
| UNOGIL | United Nations Observer Group in Lebanon |
| UNT | Untrained |
| UNTD | University Naval Training Division |
| UNTEA | United Nations Temporary Executive Authority in West Guinea |
| UNTSO | United Nations Truce Supervision Organization in Palestine |
| UNYOM | United Nations Yemen Observation Mission |
| UofT | University of Toronto |
| UofTO/STrCoy | University of Toronto Overseas Training Company |
| UPDRCAPC | Unit Pay Detachment, Royal Canadian Army Pay Corps |
| UPDT | Unit Personnel Data Transaction |
| URDIS | Your Despatch (U.S.) |
| URTP | University Reserve Training Plan |
| US | United States (of America) |
| US(A) | United States (Army) |
| USA | United States of America |
| USA | United States Army (U.S.) |
| USA | United States Army |
| USAAF | United States Army Air Force |
| USAD | United States Army Depot (or Sub-Depot) |
| USAHS | United States Hospital Ship |
| USAT | United States Army Transport (U.S.) |
| USCG | United States Coast Guard |
| USCGC | United States Coast Guard Cutter |
| USDUE | United States Distinguished Unit Emblem |
| USED | United States Engineering Department |
| USLOM | United States Naval Senior Line Officer at - |
| USMC | United States Marine Corps |
| USMNAM | United States Military, Naval and Air Mission |
| USN | United States Navy |
| USNAAB | United States Naval Advanced Amphibious Base |
| USNAATB | United States Naval Advanced Amphibious Training Base |
| USNAATSB | United States Naval Advanced Amphibious Training Sub. Base |
| USNAMSB | United States Naval Advanced Maintenance Sub. Base |
| USNATB | United States Naval Amphibious Training Sub. Base |
| USNAVPO | United States Naval Port Officers |
| USNLOS | United States Naval Liaison Officers |
| USNR | Unites States Navy Reserve |
| USNSD | United States Naval Stores and Spare Parts Depot |
| USNTSD | United States Navy Technical Division |
| USRO | United States Routing Officers |
| USS | United States Ship |
| USShip | United States Ship |
| USSR | Union of Socialist Soviet Republics |
| UT | Unsuitable for Training |
| UTO | Unit Training Officers |
| UTPM | University Training Plan (Men) |
| UTPM(CMC) | University Training Plan Men (at Canadian Military Colleges) |
| UTPM(U) | University Training Plan Men (At Civilian Universities) |
| UTPNCM | University Training Plan Non-Commissioned Members |
| UVF | Ulster Volunteer Force |
| UWOC | University of Western Ontario Contingent |