vane

Concise Oxford English Dictionary © 2008 Oxford University Press:
vane/veɪn/

▶noun

• 1 a broad blade attached to a rotating axis or wheel which pushes or is pushed by wind or water, forming part of a device such as a windmill, propeller, or turbine.

  ■ a weathervane.

• 2 a projecting surface designed to guide the motion of a projectile, e.g. a feather on an arrow.

• 3 the flat part on either side of the shaft of a feather.

– derivatives
vaned adjective.

– origin ME: dial. var. of obs. fane ‘banner’, of Gmc origin.