n.
   - 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.
 - a projecting surface designed to guide the motion of a projectile, e.g. a feather on an arrow.
 - the flat part on either side of the shaft of a feather.
 
 
  Derivative
  
  Etymology
  ME: dial. var. of obs. fane ‘banner’, of Gmc origin.