| Abbreviation | Definition |
|---|---|
| OAM | Office of Acquisitions Management |
| OAMP | Optical Aerial Measurement Program |
| OAN | Owner Applied Number |
| OAO | Original Art Only |
| OAQ | Office of Air Quality |
| OAQ | Outdoor Air Quality |
| OAR | Objectives Accountability Review |
| OAR | Office of Oceanic and Atmospheric Research |
| OAS | Office of Applied Studies |
| OASDHI | Old Age, Survivors, Disability, and Health Insurance |
| OASI | Old Age and Survivors Insurance |
| oasi | Old Age Security Income |
| OASIS | Overseas Adoption Support And Information System |
| OASUW | Objective Anti-Surface Warfare |
| OAT | Obscene Articles Tribunal |
| OAT | Office for the Advancement of Telehealth |
| OBE | Outcome Based Evaluation |
| OBEMLA | Office of Bilingual Education and Minority Languages Affairs |
| OBIM | Office of Biometric Information Management |
| OBL | Office of Business Liaison |