| Meaning | Category |
| ROM Boot | Computing->Hardware |
| Radar Beacon | Governmental->NASA |
| Rainbow Bright | Miscellaneous->Colors |
| Randomized Block | Computing->Telecom |
| Read Binary | Computing->Assembly |
| Real Beard | Internet->Chat |
| Really Big | Internet->Chat |
| Record Book | Community->Sports |
| Record Breaker | Community->Sports |
| Record Breaking | Community->Sports |
| Red Baron (Rittmeister Baron von Richtofen) | Community->Famous |
| Red Book | Governmental->US Government |
| Red Brown | Miscellaneous->Colors |
| Red-Brown | Miscellaneous->Coins |
| Registry Backup | Computing->General |
| Remote Backup | Computing->Networking |
| Requires Bind | Community->Media |
| Reservation Bit | Computing->Assembly |
| Resident Bangladeshis | Regional |
| Resistance Barrier | Academic & Science->Electronics |
| RetinoBlastoma | Medical->Physiology |
| Revenue Book | Business->Accounting |
| Review Board | Governmental->Military |
| Rich Baller | Community->Sports |
| Rich Burn | Miscellaneous->Colors |
| Richard Bruce | Computing->File Extensions |
| Right Back | Community->Sports |
| Right Brain | Medical->Physiology |
| Rigid Body | Academic & Science->Physics |
| Roast Beef | Miscellaneous->Food |
| Rob Berridge | Community->Famous |
| Rocky Blue | Miscellaneous->Colors |
| Room Booking | Business->General |
| Room and Board | Community->Housing |
| Rotate Buffer | Computing->Assembly |
| Rounded Box | Computing->General |
| Rubber Ball | Community->Sports |
| Rubber Bullet | Community->Law |
| Rubberized Base | Academic & Science->Electronics |
| Rubidium | Academic & Science->Chemistry Academic & Science->Electronics |
| Running Back | Community->Sports |
| The Raging Bears | Miscellaneous->Funnies |
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