| SI | System of International Units (Systeme International D'unites) |
|---|---|
| SI | International System of Units [Fr. le Systeme International d'Unites]; sacroiliac; saline infusion; saline injection; saturation index; self-inflicted; sensory integration; septic inflammation; serious illness; serum iron; severity index; sex inventory; signal intensity; Singh Index; single injection; small intestine; social interaction; soluble insulin; spirochetosis icterohaemorrhagica; stimulation index; stress incontinence; stroke index; sucrase isomaltase; suppression index |
| Si | the most anterior point on the lower contour of the sella turcica [point]; silicon |
| SI joint | Sacro-Iliac joint |
| SI-HRDS | structured interview Hamilton rating scale for depression |
| SIA | serum inhibitory activity; stress-induced analgesia; stress-induced anesthesia; subacute infectious arthritis |
| SIADH | Syndrome of Inappropriate secretion of Anti-Diuretic Hormone; 항이뇨 호르몬 분비 이상 증후군 |
| SIADH | syndrome of inappropriate secretion of antidiuretic hormone |
| SIB | self-injurious behavior |
| sib, sibs | sibling, siblings |