| Abbreviation | Definition |
|---|---|
| SS-21 | Scarab Missile |
| SS-23 | Spider Missile |
| SSA | Software Support Activity |
| SSA | Soldier Store Advance |
| SSA | Source Selection Authority |
| SSA | Space Situational Awareness |
| SSA | Special Support Activity (NSA) |
| SSA | Staff Support Activity |
| SSA | Standard Small Arms |
| SSA | Strapdown Sensor Assembly |
| SSA | Supply Support Activity |
| SSA | Supply Support Area |
| SSA | System Specification for ATCCS (Army Tactical Command and Control System) |
| SSA | System Supportability Assessment |
| SSAA | System Security Authorization Agreement |
| SSAC | Source Selection Advisory Council |
| SSADA | Sense, Search And Destroy Armor |
| SSAFA | Soldiers', Sailors' and Airmen's Families Association (UK) |
| SSAS | Ship Specific Alerting System |
| SSAT | Sea Special Assault Team |