| Abbreviation | Definition |
|---|---|
| SLY | Silverdale Lutheran Youth |
| SLY | St Luke Youth |
| SLYB | Silver Lake Youth Basketball |
| SLYB | Southern Lehigh Youth Basketball |
| SML | Smile |
| SML | Super Mario Logan |
| SMPY | Study of Mathematically Precocious Youth |
| SMY | Sexual Minority Youth |
| SMY | South Meridian Youth |
| SMY | Sydney Muslim Youth |
| SMYB | San Marcos Youth Baseball |
| SMYD | Society for Makalla Youth Development |
| SMYS | San Marcos Youth Soccer |
| SMYS | St Mary's Youth Soccer |
| SNYC | Samoa National Youth Council |
| SNYC | Seychelles National Youth Council |
| SNYC | Southern Negro Youth Congress |
| SNYO | Singapore National Youth Orchestra |
| SOS | Student Outreach Services |
| SOSY | Survivors Of Suicide Youth |