"ancient tool for scraping the skin after a bath," 1580s, from Latin strigilis "scraper, horse-comb," from stringere (1) "draw along a surface, graze, touch lightly; strip off, pluck off, cut away; clip, prune; lay bare, unsheathe," figuratively "waste, consume, reduce; touch, move, affect, cause pain," from PIE root *strig- "to stroke, rub, press" (source also of Latin striga "stroke, strike, furrow," stria "furrow, channel;" Old Church Slavonic striga "shear;" Old English stracian "to stroke;" German streichen "to stroke, rub").
Etymologists dispute over whether this is connected to Latin stringere (2) "to tie, tighten," root of strain (v.). Based on the sense differences, de Vaan writes, "It appears that a merger occurred of two different PIE verbs, *strig- 'to brush, strip' and *strengh- 'to tie'."
1818, "act of crawling," from crawl (v.). In the swimming sense from 1903; the stroke was developed by Frederick Cavill, well-known English swimmer who emigrated to Australia and modified the standard stroke of the day after observing South Seas islanders. So called because the swimmer's motion in the water resembles crawling. Meaning "slow progress from one drinking place to another" is by 1883.
late 15c., "shot, missiles;" later "a stroke in drawing, a short line" (1580s), from French trait "line, stroke, feature, tract," from Latin tractus "drawing, drawing out, dragging, pulling," later "line drawn, feature," from past participle stem of trahere "to pull, draw" (see tract (n.1)). Sense of "particular feature, distinguishing quality" in English is first recorded 1752.
"sudden, unforeseen occurrence," 1779, from French coup de foudre, literally "stroke of lightning," also "love at first sight" (see coup).