| RRI | recurrent respiratory infection; reflex relaxation index; relative response index |
|---|---|
| RRIS | recurrent respiratory infection syndrome |
| RRL | Registered Record Librarian |
| RRM | ribonucleotide reductase M |
| RRN | returning [for advanced studies] registered nurse |
| rRNA | ribosomal ribonucleic acid |
| rRNP | ribosomal ribonucleoprotein |
| RRP | relative refractory period |
| RRpm | respiratory rate per minute |
| RRR | regular rhythm and rate; renin release rate (or ratio) |