| EXTRASYSTOLES | • extrasystoles n. Plural of extrasystole. • EXTRASYSTOLE n. a premature beat of one of the chambers of the heart that leads to momentary arrhythmia. |
| OSTEOPLASTIES | • osteoplasties n. Plural of osteoplasty. • OSTEOPLASTY n. plastic surgery on bone. |
| PLASTERSTONES | • PLASTERSTONE n. gypsum. |
| SCLEROTITISES | • SCLEROTITIS n. inflammation of the sclerotic, also SCLERITIS. |
| SECTIONALISTS | • sectionalists n. Plural of sectionalist. • SECTIONALIST n. an adherent of sectionalism. |
| SELECTIONISTS | • selectionists n. Plural of selectionist. • SELECTIONIST n. one who considers natural selection a fundamental factor in evolution. |
| SILHOUETTISTS | • silhouettists n. Plural of silhouettist. • SILHOUETTIST n. one who makes silhouettes. |
| STADDLESTONES | • staddle␣stones n. Plural of staddle stone. • STADDLESTONE n. a low mushroom-shaped arrangement of a conical and flat, circular stone, used as a support for a haystack. |
| STEGOPHILISTS | • STEGOPHILIST n. one who climbs buildings for sport. |
| STIGMASTEROLS | • stigmasterols n. Plural of stigmasterol. • STIGMASTEROL n. a crystalline sterol obtained esp. from soybean oil. |
| STILBOESTROLS | • stilboestrols n. Plural of stilboestrol. • STILBOESTROL n. a synthetic oestrogen, also STILBESTROL. |
| STREPTOLYSINS | • streptolysins n. Plural of streptolysin. • STREPTOLYSIN n. an antigenic hemolysin produced by streptococci. |
| STREPTOSOLENS | • STREPTOSOLEN n. an evergreen solanaceous flowering shrub of the genus Streptosolen, with panicles of tubular orange flowers. |
| TESSELLATIONS | • tessellations n. Plural of tessellation. • TESSELLATION n. fitting together exactly; leaving no spaces. |
| TONSILLITISES | • TONSILLITIS n. inflammation of the tonsils, also TONSILITIS. |