| Abbreviation | Definition |
|---|---|
| OCCAM | Ocean Circulation and Climate Advanced Modelling |
| OCD | Ocean Chemistry Division |
| OCEANAV | Oceanographer of the Navy |
| OCLC | Online Computer Library Center |
| OCLIPS | Operational Climate Prediction and Services |
| OCMB | Offshore Clam Management Board |
| OCN | Oceanography |
| OCNMAP | Ocean Map |
| OCNS | Oceans, large body of water which covers most of the Earth, see sea. |
| OCR | Office of Civil Rights |
| OCRD | Ocean Climate Research Division |
| OCRM | Ocean and Coastal Resource Management |
| OCRM | Office of Coastal Resource Management |
| OCS | Office of the Chief Scientist |
| OCS | Outer Continental Shelf |
| OCSAB | Outer Continental Shelf Advisory Board |
| OCSEAP | Outer Continental Shelf Environment Assessment Program |
| OD | Optical Density |
| OD | Optical Depth |
| ODAS | Ocean Data Acquisition Systems, Aids and Devices |