| Abbreviation | Definition |
|---|---|
| SID | State Identification Number |
| SIEV | Suspect Illegal Entry Vessel |
| SIEV | Suspected Illegal Entry Vehicle |
| SIEV | Suspected Illegal Entry Vessel |
| SII | Self Inflicted Injuries |
| SII | Simulated Iterator And Inquisitor |
| SIJ | Sistema de Informacion Juvenil |
| SIJ | Special Immigrant Juvenile |
| SIK | Sanity In Killing |
| SIK | Seriously Insane Killas |
| SILE | Singapore Institute of Legal Education |
| SINAC | Skateboarding Is Not A Crime |
| SIP | Semiconductor Intellectual Property |
| SIP | Shooting Is Pointless |
| SIR | Silencing Information Regulator |
| SIR | Speed Integrity And Reliability |
| SIS | Suspended Imposition of Sentence |
| SIT | Self Inflicted Trial |
| SIT | Special Intervention Team |
| SIT | Specialized Intervention Team |