| Abbreviation | Definition |
|---|---|
| SIDS | Small Island Developing States |
| SIR | Southern Indiana Region |
| SIS | Staten Island Sound |
| SISRI | Small Island States Resilience Initiative |
| SISRI | Small Islands States Resilience Initiative |
| SL | Saint Louis |
| SLC | Salt Lake City |
| SLEB | State Law Enforcement Bureau |
| SLO | San Luis Obispo, California |
| SLRC | San Luis Rio Colorado |
| SMCR | States Marine Corps Reserve |
| SMNP | Simen Mountain National Park |
| SOC | South Orange County |
| SOCAL | Southern California |
| SOM | State Of Michigan |
| SoMi | South Miami, Florida |
| SOO | Sault Ste. Marie, Michigan |
| SOTS | State Of The States |
| SPI | South Padre Island, Texas |
| SRMS | Subtree Right Most States |