/fip"euhl/ , n. Music.
a plug stopping the upper end of a pipe, as a recorder or a whistle, and having a narrow slit through which the player blows.
[ 1620-30; perh. special use of dial. fipple loose lower lip, pouting lip; cf. ON flipi lower lip of a horse, Norw flipe flap, lappet. See FLIP 1 , FLAP, FLABBY ]