| OS | left eye [Lat. oculus sinister]; occipitosacral; occupational safety; office surgery; Omenn syndrome... |
|---|---|
| ND, nD | refractive index |
| nD | refractive index |
| ref | ind refractive index |
| RI | radiation intensity; radioactive isotope; radioimmunology; recession index; recombinant inbred [stra... |