The story
Origin uncertain. Probably from cord + duroy (“a 17th century coarse fabric made in England”). Probably not from French *corde du roi (“cloth of the king”), which is unattested in French, where the term for the corduroy is velours côtelé. Possibly from cordesoy from corde de soie (“rope of silk or silk-like fabric”), named for example in a 1756 advertisement for clothing fabrics; see Wikipedia article, and comparable in language form to the contemporary serg(e)dusoys (“silk serge”), see Serge (fabric).
Etymology from Wiktionary, CC BY-SA 4.0.