Vane

n.	1.
	1.	A contrivance attached to some elevated object for the purpose of showing which way the wind blows; a weathercock. It is usually a plate or strip of metal, or slip of wood, often cut into some fanciful form, and placed upon a perpendicular axis around which it moves freely. Aye undiscreet, and changing as a vane. - Chaucer.
	2.	Any flat, extended surface attached to an axis and moved by the wind; as, the vane of a windmill; hence, a similar fixture of any form moved in or by water, air, or other fluid; as, the vane of a screw propeller, a fan blower, an anemometer, etc.
	3.	(Zool.) The rhachis and web of a feather taken together.
	4.	One of the sights of a compass, quadrant, etc. Vane of a leveling staff (Surv.) Same as Target, 3.

Noun	1.	vane - flat surface that rotates and pushes against air or water Synonyms: blade
	2.	vane - mechanical device attached to an elevated structure; rotates freely to show the direction of the wind Synonyms: weather vane, weathervane, wind vane
	3.	vane - a metal fin attached to the tail of a bomb or missile in order to stabilize or guide it
	4.	vane - the flattened weblike part of a feather consisting of a series of barbs on either side of the shaft Synonyms: web

mechanical device, weather vane, weathercock, weathervane, wind tee, wind vane