A weather vane.
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.
One of the metal guidance or stabilizing fins attached to the tail of a bomb or other missile.
The flattened, web-like part of a feather, consisting of a series of barbs on either side of the shaft.
A device that circulates fresh air and expels stale or noxious air.
A machine that moves breathable air into and out of the lungs of a patient who is unable to breathe sufficiently.
Some behaviour or happening that relieves a tense atmosphere or situation.