A fin on the tail of an aircraft, vertical stabilizer
A fin at the tail of a fish, caudal fin
A fin-like projection at the rear of a car, common on American cars of the 1950s.
One of the metal guidance or stabilizing fins attached to the tail of a bomb or other missile.
Any of several usually relatively thin, rigid, flat, or sometimes curved surfaces radially mounted along an axis, as a blade in a turbine or a sail on a windmill, that is turned by or used to turn a fluid.
A sight on a sextant or compass.
The flattened, web-like part of a feather, consisting of a series of barbs on either side of the shaft.
A weather vane.