| Abbreviation | Definition |
|---|---|
| RDSI | Reynolds Depression Screening Inventory |
| RDT | Retinal Damage Threshold |
| RE | Right Eye |
| REC | Rear End Collision |
| REC | Receive |
| REC | Recommend |
| REC | Recurrent |
| RED | Reduce |
| RED | Reduction |
| RED | Rnasel Enzyme Dysfunction |
| REHAB | Re-Habilitate |
| REL | Recommended Exposure Limit |
| REL | Release |
| REM | Random Eye Movement |
| REM | Real Ear Measurements |
| REM | Removal |
| REMS | Rapid Eye Movement Sleep |
| REMS | Risk Evaluation and Mitigation Strategy |
| REO | Respiratory Enteric Orphan |
| REP | Roentgen Equivalent Physical |