| Abbreviation | Definition |
|---|---|
| SIS | Sister |
| SIS | Stud In Spandex |
| SIS | Super Intelligent Sister |
| SITD | Still In The Dark |
| SITL | Sky Is The Limit |
| SIUBC | S*** It Up Butter Cup |
| SIUBC | Suck It Up Butter Cup |
| SIV | Sorry I Vanished |
| SIWY | Since I Was Young |
| SIYI | Something In Your Inbox |
| SK | Still Kissing |
| SK8 | Skate |
| SK8ER | Skater |
| SK8ING | Skating |
| SK8R | Skater |
| SK8S | Skates |
| SKA | Sender Keeps All |
| SKA | Sometimes Known As |
| SKA | Super Kick A** |
| SKOL | Someone Keeps On Loving |