| SIS | semantic indexing system; serotinin irritation syndrome; simian sarcoma; simulator-induced syndrome; social information system; spontaneous interictal spike; sterile injectable solution; sterile injectable suspension |
|---|---|
| SISH | Stage I Systolic Hypertension in the Elderly [study] |
| SISI | short increment sensitivity index |
| SISS | Sentinel Injury Surveillance System [for Gunshot and Stab Wounds] small inducible secreted substances |
| SISV, SiSV | simian sarcoma virus |