| ORD | optical rotatory dispersion; oral radiation death |
|---|---|
| OSA | obstructive sleep apnea; Office of Services to the Aging; Optical Society of America; ovarian sectio... |
| ORD | Optical rotatory dispersion |
|---|---|
| OTF | Optical transfer functions |
| ROA | Raman Optical Activity |
| SNOM | Scanning near-field optical microscopes |