Definition of: flap

(flap) noun
1. A broad, limber, and loosely hanging part or attachment.
2. The act of flapping.
3. An implement for brushing away flies.
4. Surg. A piece of skin or flesh cut away except at its base.
5. The flapping tongue of a valve.
6. plural A disease of the lips of horses.
7. Aeron. A movable hinged section along the rear or trailing edge of a wing of an airplane, used to increase drag.
8. Slang An agitated or tempestuous reaction. [<v.]
—v. flapped, flap·ping v.t.
1. To move by beating: to flap the wings.
2. To move with a flapping sound.
3. To strike with something flat and flexible.
—v.i.
4. To beat the wings or move by beating the wings.
5. To move to and fro, as if blown by the wind.
6. Slang To lose one's composure. [Imit.]