| Abbreviation | Definition |
|---|---|
| SHADE | Super Human Advanced Defense Executive |
| SHAZAM | Solomon, Hercules, Atlas, Zeus, Achilles and Mercury |
| SHIELD | Strategic Hazard Intervention Espionage Logistics Directorate |
| SHIELD | Strategic Homeland Intervention, Enforcement, and Logistics Division |
| SHIELD | Supreme Headquarters, International Espionage, Law-Enforcement Division |
| SHIT | Super Hydraulic Instantaneous Transporter |
| SIA | Samurai In Action |
| SIC | Strategy Informer Clan |
| SIF | Structural Integrity Field |
| SIN | Smuggler Interstellar Network |
| SIT | Semi Intellegent Terrestrial |
| SITE | Supernatural Intuitive Transmundane Entity |
| SIX | Search for Interuniversal Xtraterrestrials |
| SK | Saber Knights |
| SK | Sith Knight |
| SK | Storm Kestrel |
| SKC | Soul Keepers Clan |
| SKD | Scavenger's Knights Of Death |
| SKEET | Super Kristian Elite Elohim Troopers |
| SKoDA | Swan Knights of Dol Amroth |