A water wheel is a large wheel which is turned by water flowing through it. Water wheels are used to provide power to drive machinery
wheel that is turned by the force of flowing water (used to operate machinery, mills, etc.)
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