1. (n.) 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.

2. (n.) 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. (n.) The rhachis and web of a feather taken together.

4. (n.) One of the sights of a compass, quadrant, etc.

Mach meter accelerometer anemograph anemometrograph anemoscope cock ground log harpoon log log log line patent log speedometer tachometer taffrail log vane weather vane weathercock wind cone wind gauge wind indicator wind sock wind vane wind-speed indicator