Flap n.  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.