'Water wheel' definitions:

Definition of 'water wheel'

noun

A wheel with buckets attached to its rim; raises water from a stream or pond [syn: waterwheel, water wheel]

noun

A wheel that rotates by direct action of water; a simple turbine [syn: waterwheel, water wheel]

From: GCIDE

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]