| Abbreviation | Definition |
|---|---|
| OSS | Optical Surveillance System |
| OSS-RC | Operations Support System - Radio and Core |
| OST | Observed Sectional Trial |
| OST | Operation Stress Test |
| OSURG | Office of the Surgeon |
| OSUT | One Station Unit Training |
| OSUT | On-Site User Test(ing) |
| OSV | Ocean Station Vessel |
| OSVA | Off-Site Vital Area |
| OSW | operation specialist weapon |
| OSW | Operational Special Weapon |
| OT | Officer Trainee |
| OT | Open Target |
| OT | Operational Test(ing) |
| OT | Operations and Training |
| OT | Opportunities and Threats |
| OT | Original Trainer |
| OT | Other Tenants |
| OT | Overtime |
| OT&E | Operational Test and Evaluation |