noun (n)

• mechanical device attached to an elevated structure; rotates freely to show the direction of the wind(noun.artifact)

  Synonym:
  weather vane, weathervane, wind vane
  

  source: wordnet30
• a fin attached to the tail of an arrow, bomb or missile in order to stabilize or guide it(noun.artifact)

  source: wordnet30
• flat surface that rotates and pushes against air or water(noun.artifact)

  Synonym:
  blade
  

  source: wordnet30
• the flattened weblike part of a feather consisting of a series of barbs on either side of the shaft(noun.animal)

  Synonym:
  web
  

  source: wordnet30
• 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.(noun)

  source: webster1913