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.
same as target.
Origin: OE. & E. Prov. E. Fane weathercock, banner, AS. Fana a banner, flag; akin to D. Vaan, G. Fahne, OHG. Fano cloth, gund fano flag, Icel. Fani, Sw. Fana, Dan. Fane, Goth. Fana cloth, L. Pannus, and perhaps to Gr. A web, a bobbin, spool. Cf. Fanon, Pane a compartment, panel.