| Abbreviation | Definition |
|---|---|
| SSID | Supplemental Security Income Disability |
| SSIU | Social Security Information Unit |
| SSP | State Supplemental Payment |
| SSP | Statutory Sick Pay |
| SSP | Strategic Systems Platform |
| SSR | Social Security Recipient |
| SSR | Soviet Socialist Republic |
| SSS | Selective Service System |
| SSS | Social Security Sequence |
| SSS | Social Security System |
| SSS | Special Scientific Study |
| SSS | System/Subsystem Specification |
| SST | Study Service Term |
| SSTG | Sector Specific Technical Group |
| ST | Scientific and Technical |
| ST | Special Treatment |
| ST | Structure of Taxes |
| ST&A | Space Technology and Aeronautics |
| STA | Special Temporary Authorization |
| STAC | Science and Technology Advisory Council |