water wheel

from WordNet (r) 3.0 (2006)

water wheel
    n 1: a wheel with buckets attached to its rim; raises water from
         a stream or pond [syn: {waterwheel}, {water wheel}]
    2: a wheel that rotates by direct action of water; a simple
       turbine [syn: {waterwheel}, {water wheel}]

from The Collaborative International Dictionary of English v.0.48

Water wheel \Wa"ter wheel`\
   1. Any wheel for propelling machinery or for other purposes,
      that is made to rotate by the direct action of water; --
      called an {overshot wheel} when the water is applied at
      the top, an {undershot wheel} when at the bottom, a
      {breast wheel} when at an intermediate point; other forms
      are called {reaction wheel}, {vortex wheel}, {turbine
      wheel}, etc.
      [1913 Webster]

   2. The paddle wheel of a steam vessel.
      [1913 Webster]

   3. A wheel for raising water; a noria, or the like.
      [1913 Webster]