| Abbreviation | Definition |
|---|---|
| OSU | Oregon Soviet University |
| OSU | Oregon Spam University |
| OSU | Organized Socialist University |
| OTB | On The Boards |
| OTC | Oh Those Clowns |
| OTC | Other Than Clinton |
| OTG | Over The Gun |
| OTH | Oh The Horror |
| OTL | Orange Tree Licker |
| OTLO | On The Look Out |
| OTM | Other Than Miata |
| OTP | On The Potty |
| OTTWD | Onwards Towards Total World Domination |
| OU | Oklahoma Utopia |
| OU | Overhyped Underachievers |
| OU | Overrated University |
| OUAM | Once Upon a Mattress |
| OUARONS | Once Upon A Royal One Night Stand |
| OWACA | Organisation Without A Cool Acronym |
| OWACA | Organization Without A Cool Acronym |