| OET | oral endotracheal tube; oral esophageal tube |
|---|---|
| OHI | Occupational Health Institute; operative hypertension indicator; oral hygiene index; Oral Hygiene In... |
| OC | 1) Osteo-Calcin 2) Oral Contraceptive |
| OCG | Oral Cholecysto-Graphy |
| OCs | Oral Contraceptives |