fin

noun

2.
one of a pair of decorations projecting above the rear fenders of an automobile
Derived from:
fin
3.
one of a set of parallel slats in a door or window to admit air and reject rain
4.
a shoe for swimming; the paddle-like front is an aid in swimming (especially underwater)
Derived from:
fin
5.
a stabilizer on a ship that resembles the fin of a fish
6.
organ of locomotion and balance in fishes and some other aquatic animals
Derived from:
fin