| Abbreviation | Definition |
|---|---|
| NWOC | National Warbird Operator Conference |
| NWOC | National Warbird Operators Conference |
| NWSC | Northern Westchester Swim Conference |
| NYF | National Youth Forum |
| NYMC | National Youth Ministry Conference |
| NYS | National Youth Summit |
| NYSC | New York Summer Conference |
| NZDC | New Zealand Discourse Conference |
| OAC | Office Automation Conference |
| OAE | Topical Meeting on Optics in Adverse Environments |
| OAMC | Ohio Area Minister Confer |
| OAMC | Older Adult Ministry Conference |
| OAPC | Ohio Asphalt Paving Conference |
| OASIS | Organization to Assess Strategies for Ischemic Syndromes |
| OAW | Oracle AppsWorld |
| OBEC | Ohio Broadcast Engineering Conference |
| OBTC | Organizational Behavior Teaching Conference |
| OCAC | Ohio Collegiate Athletic Conference |
| OCAC | Oklahoma Collegiate Athletic Conference |
| OCC | Ohio Cardinal Conference |