Flap may refer to: Arts, entertainment, and media Flap (film), a 1970 American film Flap, a boss character in the arcade game Gaiapolis Flap, a minor character in the film Little Nemo: Adventures in Slumberland Biology and healthcare Flap (surgery), a surgical technique involving movement of vascularized tissue Free flap, a specific kind of surgical flap 5-lipoxygenase activating protein (FLAP) Computing and networks The phenomenon of some variable or resource oscillating or alternating rapidly between two states Route flapping, when a network router flips between different routes Link flap, errant behavior in a communications link Engineering and design Flap (aeronautics), a lift augmentation device on an airplane wing, often near the trailing edge Flapping, the up-and-down motion of a helicopter rotor Flap, any hinged plate often used as a cover or a simple one-way valve Sluice or flap gate, a pressure driven water flow control device between a channel and other water body Bum flap (or butt flap), a separately removable part of underwear (un)covering the buttocks Mudflap, a guard for tires Pet door or pet flap Roof flap, an aerodynamic feature of race cars Linguistics Flap consonant, a sound produced by brief contact between one articulator (such as the tongue) and another (such as the roof of the mouth) Flapping, a process by which a or a before an unstressed vowel is pronounced as a flap consonant Other uses Flapping, one of the basic mechanics of bird flight Hand flapping, a common form of self-stimulatory behaviour See also Flapper (disambiguation) sk:Klapka