A pet door.

A doggie door.

plural of flapped outfall

plural of flap gate

plural of flapping hinge

(chiefly in plural) A publishing format of a paperback book with folded flyleaves, or either of the two flyleaves so folded.

(slang) The flap for defecation in a union suit.

(surgery) The use of a flap made from a patient's conjunctiva to replace a damaged section of cornea.

A small tab projecting from the trailing edge of a wing, used on racecars and aircraft.

present participle of flip-flap