| Abbreviation | Definition |
|---|---|
| RFDC | Recreational Folk Dancers of Columbus |
| RFMI | Reale Federazione Motociclistica Italiana |
| RG | Really Great |
| RGC | RAND Genealogy Club |
| RH | Rare Hunter |
| RITS | Rock Island Technical Society |
| RJ | Record Junkie |
| RKA | Raven Kindred Association |
| RMC | Ravenclaw Muggles Club |
| RMM | Red Mountain Modelers |
| RMPT | Rocky Mountain Paintball Tournament |
| RNING | Running |
| RO | Ragnarok Online |
| ROC | Redline Owners Club |
| ROC | Rotors Over Carolina |
| ROCC | Reading Old Cavers Club |
| ROCK | Raisers Of Contagious Killing |
| ROCKET | Recumbents Of Central Knoxville and East Tennessee |
| ROTK | Return Of The King |
| ROTK | Romance Of the Three Kingdoms |