| Abbreviation | Definition |
|---|---|
| OSA | Operational Services Agreement |
| OSA | Operational Support Airlift |
| OSAF | Optimally Stationing Army Forces |
| OSAMA | Oh Shit! American Missiles Again! |
| OSAT | Out-Of-Service Analog Test |
| OSB | Officer Selection Board |
| OSB | Oriented Stand Board |
| OSC | Objective Supply Capability |
| OSC | Offensive Space Control |
| OSC | Officers' Spouses Club |
| OSC | One Shot Chambered |
| OSC | On-Scene Commander |
| OSC | On-Site Commander |
| OSC | Operation Support Center |
| OSC | Operational Support Command |
| OSC | Operations Support Cell |
| OSCAR | Orbital Satellite Carrying Amateur Radio |
| OSCAR | Outside Cable Rehabilitation |
| OSCE | Organization For Security and Cooperation In Europe |
| OSCR | Operations and Support Cost Reduction |