| Abbreviation | Definition |
|---|---|
| ONO | Organization of News Ombudsmen |
| ONR | Oklahoma News Report |
| ONT.PARL | Ontario Legislative Television Satellite Network |
| ONW | Ocean News Weekly |
| OOQ | Occupational Outlook Quarterly |
| OOR | Occupational Outlook Report |
| OOV | Out Of Variance |
| OP-ED | OPinion EDitorial |
| OP-ED | OPposite the EDitorial page |
| OPL | Open Publication License |
| OPN | Optics and Photonics News |
| OPR | Overflow Press Room |
| ORX | Operational Receiver |
| OS | Outside Source |
| OSN | O Scale News |
| OSN | Orbit Showtime Network |
| OSRTC | Ontario Sound Recording Tax Credit |
| OTI | OnTheInternet |
| OTP | Over The Page |
| OTWOL | On the Wings of Love |