The wing of a helicopter or other rotary-wing aircraft.
A rotating part of a mechanical device; for example, in an electric motor, generator, alternator, or pump.
A type of powerful horizontal-axis atmospheric vortex generated by the interaction of strong winds with mountainous terrain.
A quantity having magnitude, direction, and position.
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.