"rough silk," 1759, perhaps from French floche "tuft of wool" (16c.), from Old French floc "tuft, lock," from Latin floccus "tuft of wool." Or from an unrecorded Old English or Old Norse word from the root found in Dutch flos "plush" (17c.). Cf. the surname Flossmonger, attested 1314, which might represent a direct borrowing from Scandinavian or Low German. In "The Mill on the Floss" the word is the proper name of a fictitious river in the English Midlands.