| Abbreviation | Definition |
|---|---|
| SIAD | Sierra Army Depot |
| SIAD | Statistical Information Analysis Division |
| SIAGL | Survey Instrument Azimuth Gyroscope Lightweight |
| SIAM | elf-Initiated Antiaircraft Missile |
| SIAM | Self-Initiated Antiaircraft Missile |
| SIAS | Slightly Increased Attack Speed |
| SIB | Singapore Infantry Brigade |
| SIB | Soldiers In Battle |
| SIBYL | Synergistic Image Building Yttrium LADAR |
| SIC | Score Information Criterion |
| SIC | Second In Command |
| SIC | Special Industry Code |
| SIC | Standard Industry Classifications |
| SIC | Subject Identification Code |
| SIC | Survey Information Center |
| SIC | System Integration Contractor |
| SICC | Safeguard Inventory Control Center |
| SICC | Service Item Control Center |
| SICCGS | Surrender Is Cowardice; Cowards Get Shot |
| SICO | Sector Interface Control Officer |