| Abbreviation | Definition |
|---|---|
| OHH | Oklahoma Heart Hospital |
| OHI | Optimum Health Institute |
| OHI | Organizational Health Inventory |
| OHI | Other Health Impairment |
| OHI | Other Health Insurance |
| OHP | Object Health Points |
| OHPE | Office of Hospital Physical Environment |
| OHRI | Ottawa Hospital Research Institute |
| OHRR | Open Heart Recovery Room |
| OHRU | Open Heart Recovery Unit |
| OHU | Occupational Health Unit |
| OI | Orthopedic Impairment |
| OICU | Obstetric Intensive Care Unit |
| OICU | Oncology Intensive Care Unit |
| OICU | Orthopedic Intensive Care Unit |
| OIS | Optical Intrinsic Signal |
| OLLH | Our Lady of Lourdes Hospital |
| OLT | Orthotopic Liver Transplant |
| OMFS | Oral and MaxilloFacial Surgery |
| OMH | Ontonagon Memorial Hospital |