| Abbreviation | Definition |
|---|---|
| NRD | National Radio Day |
| NRRL | Norwegian Radio Relay League |
| NRRT | Newton Amateur Radio Response Team |
| NTS | National Traffic System |
| OAR | 'ON-AIR-RALLIES' |
| OD | Omni-Directional |
| OOC | Official Observer Corps |
| OOS | Official Observer Station |
| OP | Over-Powered |
| OPARS | Old Post Amateur Radio Society |
| OQ | Operator Qualification |
| OQP | Ohio QSO Party |
| OQP | Ontario QSO Party |
| ORN | Omega Radio Network |
| ORRA | Off-Road Radio Association |
| OTP | On The Porch |
| PABX | private automatic branch exchange |
| PAR | Parabolic Aluminum Reflector |
| PARA | Philippine Amateur Radio Association |
| PARC | Palomar Amateur Radio Club |