efficience

CIDE DICTIONARY

efficience, n. [L. efficientia.].

The quality of being efficient or producing an effect or effects; efficient power; effectual agency. [1913 Webster]
"The manner of this divine efficiency being far above us." [1913 Webster]
The ratio of useful work to energy expended. Rankine. [1913 Webster]

efficiency of a heat engine, the ratio of the work done by an engine, to the work due to the heat supplied to it.

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