| OAD | obstructive airway disease; organic anionic dye |
|---|---|
| OH | hydroxycorticosteroid; obstructive hypopnea; occipital horn; occupational health; occupational histo... |
| OLD | obstructive lung disease; orthochromatic leukodystrophy |
| OSA | obstructive sleep apnea; Office of Services to the Aging; Optical Society of America; ovarian sectio... |
| OSAS | obstructive sleep apnea syndrome |