– ORIGIN late 15th century (as an adjective): from Geane, former English name of the city of ‘Genoa’(Old French Janne, now Gênes), the place of original production. The noun sense comes from jean fustian, literally ‘fustian from Genoa’, used in the 16th century to denote a heavy twilled cotton cloth.
jean
EnglishOxford Dictionary of English