| SI | International System of Units [Fr. le Systeme International d'Unites]; sacroiliac; saline infusion; ... |
|---|---|
| SID | single intradermal [test]; Society for Investigative Dermatology; sucrase-isomaltase deficiency; sud... |
| SIMA | single internal mammary artery |
| SIR | single isomorphous replacement; specific immune release; standardized incidence ratio; syndrome of i... |
| SLA | left sacroanterior [fetal position] [Lat. sacrolaeva anterior]; single-cell liquid cytotoxic assay; ... |