| Abbreviation | Definition |
|---|---|
| SNP | sinonasal polyposis |
| SNP | sinus node potential |
| SNP | sodium nitroprusside |
| SNP | synaptophysin |
| SNR | signal to noise ratio |
| SNTN | Scottish National Training Number |
| SO | salpingo-oophorectomy |
| SO | second opinion |
| SO | secondary oocyte |
| SO | shoulder orthosis |
| SO | Side Of |
| SO | sine oculis (gene) |
| SO | sleep onset |
| SO | sphincter of Oddi |
| SO | standing orders |
| SO | suggestive of |
| SO | superior oblique |
| SO | superior olive |
| SO | superoxide |
| SO | systolic output |