| Abbreviation | Definition |
|---|---|
| R | Radians |
| R | Rankine Temperature Scale |
| R | Resistance in Ohms |
| rad | radian |
| REM | Roentgen Equivalent Man |
| REV | Revolution(s) |
| RFU | Relative Fluorescence Units |
| RH | Run Hour |
| RHA | Rolling Herd Average |
| RHP | Relative Humidity - Percent |
| RLT | Really Long Time |
| RLU | Relative Light Unit |
| RMU | Raw Material Units |
| RPH | Revolutions Per Hour |
| RPM | Rotations Per Mile |
| RPM | Rotations Per Minute |
| RPS | Requests Per Second |
| RPS | Requests Per Similar |
| RPS | Revolutions Per Second |
| RPT | Records Per Track |