| Term | Definition |
| sacchar- | sugar |
| sacr/o | sacrum (large bone at base of spine) |
| salping/o | fallopian tube |
| sanit/a | health |
| sap/o | soap |
| sapro- | rotten |
| sarc/o | flesh, connective tissue |
| -sarcoma | cancer of connective tissue |
| saur/o | lizard |
| scaph/o | boat-shaped, scapha |
| scapul/o | scapula (shoulder blade) |
| scat- | dung |
| -schisis | cleft, split |
| schisto- | split, cleft |
| schiz- | division |
| scint/i | spark |
| scirrh/o | hard, hard tumor |
| scler- | hard |
| scler/o | white of eye, hard |
| -sclerosis | abnormal hardening |
| scoli/o | curved, crooked |
| -scope | instrument used to view |
| -scopy | process of viewing |
| scot/o | darkness |
| scrot/o | scrotum |
| seb/o | sebum, oil, fatty |
| sect- | dissect, cut |
| semi- | half |
| semin/i | semen |
| sensor/i | sensory |
| -sepsis | decay caused by |
| sept/o | septum, seven |
| septi- | seven |
| ser/o | blood serum |
| sesqui- | one and one-half |
| sex- | six |
| sial/o | saliva |
| sialaden/o | salivary gland |
| sicc- | dry |
| sider/o | iron |
| sigmold/o | sigmoid colon |
| silic/o | silica, quartz |
| sinistr/o | left |
| sinus/o | sinus |
| -sis | condition |
| sito- | bread, food |
| skeleto- | skeleton |
| socio- | social, society |
| somat/o | body |
| -some | body |
| somn/o | sleep |
| son/o | sound |
| -spadia | to tear, cut |
| span/o | scarce |
| -spasm | sudden, involuntary muscle contraction |
| spasmo- | spasm |
| spectr- | image |
| sperm/o | sperm cells |
| sperma- | sperm, seed |
| sphen/o | wedge, wedge-shaped |
| sphenoid/o | sphenoid (compound bone at base of skull) |
| spher/o | sphere, round |
| sphygmo- | pulse |
| spin/o | spine |
| spir/o | to breath |
| splanchn/o | viscera |
| splen/o | spleen |
| spondyl/o | vertebra, backbone |
| spongi/o | sponge-like |
| spor/o | spore, seed |
| squam/o | scaly |
| -stabile | stable, fixed |
| -stalsis | contraction |
| staped/o | stapes (a middle ear bone) |
| staphylo- | bunch of grapes |
| -stasis | maintenance of level, prevent increase |
| -stat | agent or device for keeping something from changing |
| steat/o | fat |
| -stenosis | abnormal narrowing |
| sterc- | feces |
| stere/o | three dimensional |
| stern/o | sternum (breastbone) |
| steth/o | chest |
| sthen/o | strength |
| stich/o | rows |
| stom/o | mouth |
| stoma- | mouth |
| -stomy | new opening |
| strat/i | layer |
| strept/o | twisted |
| -stroma | connective or supportive tissue of an organ |
| sub- | under, below |
| sud/o | sweat |
| super- | above, beyond |
| supra- | above, upward |
| syn- | together |
| synaps/o | point of contact |
| syndesm/o | ligament |
| synovi/o | synovial membrane, synovial joint |
| syphil/o | syphilis |
| syring/o | tube, pipe, fistula |
| systol/o | contraction |