| IO | incisal opening; inferior oblique; inferior olive; internal os; interorbital; intestinal obstruction; intraocular; intraoperative |
|---|---|
| Io | ionium |
| IOA | inner optic anlage; International Osteopathic Association |
| IOC | International Organizing Committee on Medical Librarianship; intern on call |
| IOCG | intraoperative cholangiogram |
| IOD | injured on duty; integrated optical density; interorbital distance |
| IOFB | intraocular foreign body |
| IOH | idiopathic orthostatic hypotension |
| IOL | induction of labor; intraocular lens |
| IOM | Institute of Medicine |