The Collaborative International Dictionary
Water wheel \Wa"ter 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.
The paddle wheel of a steam vessel.
A wheel for raising water; a noria, or the like.
Usage examples of "undershot wheel".
There was a jetty on the river, a mill with an undershot wheel and a boat shed, with smaller craft and a big two-masted flat-bottomed sailing barge that looked to be about eighty, maybe a hundred tons burden.
He was probably stuck with an overshot wheel, just because he knew how to make that work, but somewhere he had the notion that an undershot wheel was more efficient-or was it the other way around?
Its bulk loomed dark against the still lambent sky, the great round of the undershot wheel showing gaps here and there like breaks in a set of teeth.