| Abbreviation | Definition |
|---|---|
| ORP(CDER) | Office of Regulatory Policy (Center for Drug Evaluation and Research) |
| ORP(CFSAN) | Office of Regulations and Policy (Center for Food Safety and Applied Nutrition) |
| ORPS | Office of Real Property Services |
| ORPS(OC) | Office of Real Property Services (OC) |
| ORPSS | Office of Regulations, Policy, and Social Sciences |
| ORPSS(CFSAN) | Office of Regulations, Policy and Social Sciences (CFSAN) |
| ORR | objective response rate |
| ORS | Office of Regulatory Science |
| ORS | Office of Regulatory Services |
| ORS(CFSAN) | Office of Regulatory Science (CFSAN) |
| ORTF | Obesity Research Task Force |
| ORWH | Office Research into Women's Health (NIH) |
| OS(CDER) | Operations Staff (CDER) |
| OS(CDER) | Operations Staff (Center for Drug Evaluation and Research) |
| OS(CFSAN) | Office of Seafood (CFSAN) |
| OS(OC) | Operations Staff (OC) |
| OS(OC) | Operations Staff (Office of the Commissioner) |
| OSAS | Office of Scientific Analysis and Support |
| OSAS(CFSAN) | Office of Scientific Analysis and Support (CFSAN) |
| OSB | Office Services Branch |