Noun
1. any broad thin and limber covering attached at one edge; hangs loose or projects freely;
"he wrote on the flap of the envelope"2. an excited state of agitation;
"he was in a dither""there was a terrible flap about the theft"3. the motion made by flapping up and down
4. a movable piece of tissue partly connected to the body
5. a movable airfoil that is part of an aircraft wing; used to increase lift or drag