| SI | International System of Units [Fr. le Systeme International d'Unites]; sacroiliac; saline infusion; ... |
|---|---|
| SIG | small inducible gene |
| SISS | Sentinel Injury Surveillance System [for Gunshot and Stab Wounds] small inducible secreted substance... |
| SL | sarcolemma; sclerosing leukoencephalopathy; secondary leukemia; segment length; sensation level; sen... |
| SLL | small lymphocytic lymphoma |