| RGR | relative growth rate |
|---|---|
| RH | radiant heat; radiation hybrid; radiological health; reactive hyperemia; recurrent herpes; regulator... |
| RHD | radiological health data; relative hepatic dullness; renal hypertensive disease; rheumatic heart dis... |
| RI | radiation intensity; radioactive isotope; radioimmunology; recession index; recombinant inbred [stra... |
| RIM | radioisotope medicine; recurrent induced malaria; relative-intensity measure |