| Abbreviation | Definition |
|---|---|
| OPSG | Olympus Photo Safari Group |
| OQC | Our Quilting Circle |
| OQG | Omaha Quilters` Guild |
| ORE | Oregon Rockhounds Online |
| OS | Offentlig Sak |
| OTN | On The Needles |
| OTTB | Off Track Thoroughbred |
| OVM | Oregon Vintage Motorcyclist club |
| OVRC | Oklahoma Vintage Radio Collectors |
| OYC | Oysterville Yacht Club |
| P/U | Postally Used |
| PA | Paranoids Anonymous |
| PAC | Packard Automobile Classics |
| PARC | Palo Alto Run Club |
| PBA | Pro Bloggers Association |
| PBEM | Play By E Mail |
| PBEM | Play By Electronic Mail |
| PBQ | Perfume Bottle Quarterly |
| PBS | Pacific Bonanza Society |
| PC | Platina Cards |