fin

Definition
(noun) the cardinal number that is the sum of four and one Definition
(noun) one of a pair of decorations projecting above the rear fenders of an automobile Definition
(noun) one of a set of parallel slats in a door or window to admit air and reject rain Definition
(noun) a shoe for swimming; the paddle-like front is an aid in swimming (especially underwater) Definition
(noun) a stabilizer on a ship that resembles the fin of a fish Definition
(noun) organ of locomotion and balance in fishes and some other aquatic animals Definition
(verb) equip (a car) with fins Definition
(verb) propel oneself through the water in a finning motion Definition
(verb) show the fins above the water while swimming