| SDF | slow death factor; stress distribution factor |
|---|---|
| SECG | stress electrocardiography |
| SI | International System of Units [Fr. le Systeme International d'Unites]; sacroiliac; saline infusion; ... |
| s | Greek lower case letter sigma; conductivity; cross section; millisecond; molecular type or bond; pop... |
| SIH | stimulation-induced hypalgesia; stress-induced hyperthermia; suction-induced hypoxemia |