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Old English stemn, stefn "stem of a plant," also "either end-post of a ship," from Proto-Germanic *stamniz (cf. Old Saxon stamm, Old Norse stafn "stem of a ship;" Danish stamme, Swedish stam "trunk of a tree;" Old High German stam, German Stamm), from PIE root *sta- "to stand" (see stet).
Meaning "support of a wineglass" is from 1835. Stem-winding watches (1875) were advanced and desirable when introduced, hence slang stem-winder "excellent thing" (1892). The nautical sense is preserved in the phrase stem to stern "along the full length" (of a ship), attested from 1620s. The verbal phrase stems from, first recorded 1932, American English, translates German stammen aus, probably from a figurative sense represented by English stem (n.) in the sense of "stock of a family, line of descent" (c.1540; cf. family tree, and German stammvater "tribal ancestor," literally "stem-father"). Stem cell attested by 1885.
"to hold back," c.1300, from Old Norse stemma "to stop," from Proto-Germanic *stamjan (cf. Swedish stämma, Old Saxon stemmian, Middle Dutch stemon, German stemmen "stop, resist, oppose"), from PIE root *stem- "to strike against something" (cf. Lithuanian stumiu "thrust, push"). Phrase to stem the tide is literally "to hold back the tide," but often is confused with stem (v.) in sense of "to make headway against, head in a certain course" (late 14c.), which is from stem (n.)).
A supporting structure resembling the stalk of a plant.