| Abbreviation | Definition |
|---|---|
| OCMA | Oil Content Monitor and Analyzer |
| OCMI | Officer In Charge, Marine Inspection |
| OCOT | Of the Chief Of Transportation |
| OCP | Overland Common Point |
| OCPT | Orange County Public Transportation |
| OCT | Office of Community Transportation |
| OCTA | Ottawa County Transportation Agency |
| OCTD | Orange County Transportation District |
| OCTS | Overland Container Transportation Services |
| OD | Origin Destination |
| OD | Over Drive |
| ODALS | Omnidirectional Approach Lighting System |
| ODAPS | Oceanic Display and Planning System |
| ODB | Outboard Drag Boat |
| ODFL | Old Dominion Freight |
| ODFL | Old Dominion Freight Line |
| ODI | Office of Defects Investigation |
| ODL | Oceanic Data Link |
| ODMS | Operational Data Management System |
| ODO | ODOmeter |