vane

1. A weather vane.
2. 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.
3. The flattened, web-like part of a feather, consisting of a series of barbs on either side of the shaft.
4. A sight on a sextant or compass.
5. One of the metal guidance or stabilizing fins attached to the tail of a bomb or other missile.

الجمع vanes