| Abbreviation | Definition |
|---|---|
| OSCAR | Orbital Satellite Carrying Amateur Radio |
| OSCR | Ocean Surface Current Radar |
| OSDP | Operations System Development Program |
| OSF | Operation Support Facility |
| OSG | Ohio Sea Grant |
| OSJ | Ocean Science Journal |
| OSLR | Intergovernmental Committee for Ocean Science and Living Resources |
| OSM | Office of Surface Mining |
| OSN | Ocean Science News |
| OSNLR | Ocean Science in Relation to Non-Living Resources |
| OSO | Office of Systems Operations |
| OSP | On Stagnant Pond |
| OSPREY | Ocean Science Program in Recruitment and Education for Youth |
| OSS | Observing Simulation System |
| OSS | Office of Space Science |
| OSSA | Office of Space Sciences and Applications |
| OSSE | Observing System Simulation Experiment |
| OST | Ocean Science Trust |
| OST | Ocean Surface Temperature |
| OST | Office of Science and Technology |