\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.
2. The paddle wheel of a steam vessel.
3. A wheel for raising water; a noria, or the like.