| Acronym | Definition |
|---|
| UO➣University of Oregon |
| UO➣Ultima Online (game) |
| UO➣Urban Outfitters |
| UO➣Uh Oh |
| UO➣Universal Orlando (Orlando, Florida) |
| UO➣University of Oxford |
| UO➣University of Oklahoma |
| UO➣Underoath (band) |
| UO➣University of Ottawa |
| UO➣Urban Operations (game) |
| UO➣Urge Overkill (band) |
| UO➣University of Otago (New Zealand) |
| UO➣University Outreach |
| UO➣Urinary Output |
| UO➣Unusual Occurrence |
| UO➣Unexploded Ordnance |
| UO➣Undercover Officer |
| UO➣Université d'Orléans (French: University of Orleans) |
| UO➣Uru Obsession (website) |
| UO➣Unit Operator |
| UO➣Uncle Owen (Star Wars character) |
| UO➣Union Railroad of Oregon |
| UO➣Official Envelope (Scott Catalogue prefix; philately) |
| UO➣Under-Officer |
| UO➣Undelivered Orders |
| UO➣ureteric orifice |