| Abbreviation | Definition |
|---|---|
| OSI | Operational Subsystem Interface |
| OSIA | On-Site Inspection Activity |
| OSID | Objective System Interface Drawing |
| OSIFA | Operational Sequence and Info Flow Analysis |
| OSINT | Open Source Intelligence |
| OSINT | Open-Source Intelligence |
| OSIS | Open-Source Information System |
| OS-JTF | Open Systems - Joint Task Force |
| OS-JTF | Open Systems _ Joint Task Force |
| OSK | One Shot Kill |
| OSK | One Shot Kills |
| OSO | Operational Support Office |
| OSOCC | On-Site Operations Coordination Center |
| OSP | On Site Procurement |
| OSP | Operations Support Package |
| OSPG | Overseas Security Policy Group |
| OSRAP | Optimum Stockage Requirements Analysis Program |
| OSRI | Originating Station Routing Indicator |
| OSS | Office of Strategic Services |
| OSS | Operation Support System |