A flap is something that swings or moves up and down, often making a noise. It can also be an action of moving one's arms quickly to get attention.
The word "flap" has several common uses. When you're in a plane, the flaps are parts on the wings that help with landing, kind of like extra brakes. On a bird, its flapping wings make it fly, and sometimes people use their arms to flap like wings for fun or to get attention. You might see someone flapping their hands in excitement when they're happy or surprised. In addition, if something's not working properly, you could say there's a flap in the system, meaning that it's malfunctioning.
How common is "flap"?
Word flap is considered uncommon in modern English. It appears most frequently in fiction texts and less often in other writings.
Definitions
noun
Anything broad and flexible that hangs loose, or that is attached by one side or end and is easily moved.
Example: a flap of a garment
A hinged leaf.
Example: the flaps of a table
(aviation) A hinged surface on the trailing edge of the wings of an aeroplane, used to increase lift and drag.
A side fin of a ray.
The motion of anything broad and loose, or a sound or stroke made with it.
Example: the flap of a sail
A controversy, scandal, stir, or upset.
Example: The comment caused quite a flap in the newspapers.
(phonetics) A consonant sound made by a single muscle contraction, such as the sound /ɾ/ in the standard American English pronunciation of body.
(surgery) A piece of tissue incompletely detached from the body, as an intermediate stage of plastic surgery.
(slang, vulgar, chiefly in the plural) The labia, the vulva.
(obsolete) A blow or slap (especially to the face).
Example: 1450, Palladius on Husbondrieː
Ware the horn and heels lest they fling a flap to thee.
(obsolete) A young prostitute.
(graph theory) A connected component of the induced subgraph formed by deleting a set of vertices.
