Wā'ter-wheel, n.
n. 1. Any wheel for propelling machinery or other purposes, that is made to rotate by the direct action of water; — called an over-shot-wheel when the water is applied at the top, an undershot-wheel when at the bottom, a breast-wheel when at an intermediate point, and a reaction-wheel, vortex-wheel, or turbine-wheel, when its axis is vertical, and the water acts upon different sides of the wheel at the same time.
Sense 2. The paddle-wheel of a steam-vessel.