What does "vane" mean?

Vane: 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.

Additional senses

  1. 2.(Zoöl.) The rhachis and web of a feather taken together.
  2. 3.One of the sights of a compass, quadrant, etc. Vane of a leveling staff. (Surv.) Same as Target, 3.

Sources