| Abbreviation | Definition |
|---|---|
| SIS | Special Information Systems |
| SIS | Special Intelligence Service |
| SIS | Special Intelligence System |
| SIS | STOW (Synthetic Theater Of War) Infrastructure System |
| SIS | STOW Infrastructure System |
| SIS | Strategic Information System |
| SIS | System Integration and Support |
| SISMS | Standard Integrated Support Management System |
| SIT | Sensory Integration Training |
| SIT | Short Intensive Training |
| SIT | Slayers In Training |
| SIT | System Integration Test |
| SITA | Safe Impeccable Timely Action |
| SITAP | Simulation for Transportation Analysis and Planning |
| SITC | Single Integrated Test Cycle |
| SITC | SPAWAR (Space and Naval Warfare Systems Command) Information Technology Center |
| SITEREP | Situation Report |
| SITLM | Single Integrated Theater Logistic Manager |
| SITMAP | Situation Map |
| SITP | System Integration Test Plan |