| ORS | olfactory reference syndrome; oral rehydration solution; oral surgery, oral surgeon; Orthopaedic Res... |
|---|---|
| ORMC | oxygen ratio monitor controller |
| OA | obstructive apnea; occipital artery; occipito-anterior; occiput anterior; octanoic acid; ocular albi... |
| PA | panic attack; pantothenic acid; paralysis agitans; paranoia; passive aggressive; pathology; patient'... |
| OCP | octacalcium phosphate; ocular cicatricial pemphigoid; oral case presentation; oral contraceptive pil... |