- 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.]
- 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.
- [Zoöl] The rhachis and web of a feather taken together.
- One of the sights of a compass, quadrant, etc.
Etymology: OE. & Prov. E. fane weathercock, banner, AS. fana a banner, flag; akin to D. vaan, G. fahne, OHG. fano cloth, gund fano flag, Icel. fāni, Sw. fana, Dan. fane, Goth. fana cloth, L. pannus, and perhaps to Gr. ph^nos a web, phni`on a bobbin, spool. Cf. Fanon Pane a compartment, panel