| Acronym | Definition |
|---|
| OU | Oklahoma University |
| OU | Ohio University |
| OU | Open University |
| OU | Oakland University (Michigan) |
| OU | Orthodox Union |
| OU | Organizational Unit |
| OU | Oxford University |
| OU | Open Universiteit |
| OU | Operable Unit (CERCLA) |
| OU | Over/Under (sports betting) |
| OU | Osmania University (India) |
| OU | Croatia Airlines (IATA airline code) |
| OU | Open Use (zoning) |
| OU | Over Used (gaming names) |
| OU | Union of Orthodox Jewish Congregations of America (New York, NY) |
| OU | Oregon University |
| OU | Observation Unit (healthcare) |
| OU | Osaka University (Japan) |
| OU | Oglethorpe University (Atlanta, Georgia) |
| OU | Otago University (Dunedin, New Zealand) |
| OU | Ornstein-Uhlenbeck |
| OU | Origin Unknown |
| OU | Operational Unit |
| OU | Oculus Uterque (Latin: Each Eye) |
| OU | Out of Unity (Quaker religion) |
| OU | Odor Unit |
| OU | Oceanic Union (gaming) |