rhododendron - ruination
- rowlock
- Rox Roxburghshire
- Roxburghshire
- Roy
- Roy
- royal
- royal blue
- Royal demesne
- Royal Exchange
- Royal Highness
- royal mast
- royal road
- royal stag
- royalist
- royalistic
- royally
- royalty
- ROYGBIV Red Orange Yellow Green Blue Indigo Violet
- RP reprint
- rpm revolutions per minute
- RPO Railway Post Office
- rps revolutions per second
- RPV Remotely Piloted Vehicle
- RR RailRoad
- RS
- RSFSR
- RSM Royal School of Music
- RSV Revised Standard Edition
- RT Hon Right Honourable
- RT radio-telephony
- Rt Rev Right Reverend
- rt. right
- rte route
- RTF Rich Text Format
- RTTY Radio Teletype
- rub
- rub along
- rub away
- rub down
- rub in