Old English stigrap "a support for the foot of a person mounted on a horse," literally "climbing rope," from stige "a climbing, ascent" (from Proto-Germanic *stigaz "climbing;" see stair) + rap (see rope (n.)). Originally a looped rope as a help for mounting. Germanic cognates include Old Norse stigreip, Middle Dutch stegerep, Old High German stegareif, German stegreif. Surgical device used in childbirth, etc., so called from 1884. Stirrup-cup (1680s) was a cup of wine or other drink handed to a rider already on horseback and setting out on a journey, hence "a parting glass" (compare French le vin de l'etrier).
updated on December 02, 2013