| Abbreviation | Definition |
|---|---|
| OPDIN | Ocean Pollution Data INformation Center |
| OPF | Official Personnel Folder |
| OPL | Oxygenation Portable Laboratory |
| OPM | Office of Personnel Management |
| OPSD | Oceanographic Products and Services Division, NOAA |
| OR&F | Operations, Research And Facilities |
| ORCA | Oceanic Research Centre Australia |
| OREP | Ocean Resources and Ecosystems Program |
| ORF | Oceanic Resource Foundation |
| ORI | Ocean Research Institute |
| ORION | Ocean Research Interactive Observatory Network |
| ORISE | Oak Ridge Institute for Science and Education |
| ORNL | Oak Ridge National Laboratory |
| ORPP | Ocean Research Priorities Plan |
| ORSA | Operations Research Society of America |
| ORTA | Office of Research and Technology Applications |
| OSAA | Operational Satellite Active Archive |
| OSB | Ocean Studies Board |
| OSC | Ocean Science Committee |
| OSCA | Ocean Science Council of Australia |