| RRL | Registered Record Librarian |
|---|---|
| RRT | random response technique; Registered Respiratory Therapist; relative retention time |
| RT | radiologic technologist; radiotelemetry; radiotherapy; radium therapy; rapid tranquilization; reacti... |
| RTM | registered trademark |
| RTR | Recreational Therapist, Registered; red blood cell turnover rate; retention time ratio |