Flap (?), n. [OE. flappe, flap, blow, bly-flap; cf. D. flap, and E. flap, v.] Anything broad and limber that hangs loose, or that is attached by one side or end and is easily moved; as, the flap of a garment.
A cartilaginous flap upon the opening of the larynx. Sir T. Browne.
2. A hinged leaf, as of a table or shutter.
3. The motion of anything broad and loose, or a stroke or sound made with it; as, the flap of a sail or of a wing.
4. pl.(Far.) A disease in the lips of horses.
Flap tile, a tile with a bent up portion, to turn a corner or catch a drip. — Flap valve(Mech.), a valve which opens and shuts upon one hinged side; a clack valve.