"rough silk," 1759, from Fr. floche "tuft of wool," from floc, from L. floccus "tuft of wool." Or from an unrecorded O.E. or O.N. word from the root of Du. flos "plush" (17c.). In "The Mill on the Floss" the word Floss is the proper name of a fictitious river in the Eng. Midlands.