the paddle wheel of a steam vessel.
2. water wheel ·- a wheel for raising water; a noria, or the like.
3. water wheel ·- 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.