| OAM | outer acrosomal membrane |
|---|---|
| OC | obstetrical conjugate; occlusocervical; office call; on call; only child; optic chiasma; oral contra... |
| OCBF | outer cortical blood flow |
| OEE | osmotic erythrocyte enrichment; outer enamel epithelium |
| OHC | occupational health center; outer hair cell |