| Abbreviation | Definition |
|---|---|
| REDUN | Redundancy |
| REE | Remote Exploration and Experimentation |
| REED | Rocket Exhaust Effluent Diffusion |
| REEDA | Rocket Exhaust Effluent Diffusion Analysis |
| REF | Refurbish, Refurbishment |
| REFRIG | Refrigerate |
| REFSMMAT | Reference Stable Member Matrix |
| REFURB | Refurbish |
| REG | REGulator |
| REGEN | Regenerate |
| REI | Range From Entry Interface (400 K) |
| REI | Re Entry Interval |
| REI | Runway End Identification |
| REIL | Runway End Identification Lights |
| REI-M | REI-Mollite |
| REINF | Reinforce |
| REINIT | Reinitialize |
| REL | Relative |
| RELMAT | Relative Matrix |
| REM | Regular Even Movements |