| Abbreviation | Definition |
|---|---|
| SIC | Seat In Coach |
| SID | Side Impact Dummy |
| SID | Speed Indicating Device |
| SID | Standard Instrument Departure |
| SID | Static Impeller Driven |
| SIDS | Standard Instrument Departure System |
| SIDS | Sudden Import Death Syndrome |
| SIGMET | Significant Meteorological Information |
| SIIP | Springfield Interchange Improvement Project |
| SIM | Schedule of Implementation Procedures |
| SIMMOD | Airport and Airspace Simulation Model |
| SIP | Side Impact Protection |
| SIP | The Subaru Information Pages |
| SIPS | Side Impact Protection System |
| SIRTOA | Staten Island Rapid Transit Operating Authority |
| SIT | Storage In Transit |
| SITB | Sit In The Back |
| SITC | Shandong International Transportation Corporation |
| SITC | Standard Industrial Trade Classification |
| SITS | Southern Indiana Transit System |