EFFICIENCE

{ Ef‐fi″cience (?), Ef‐fi″cien‐cy (?), } n. [[L. efficientia.]] 1. 1. The quality of being efficient or producing an effect or effects; efficient power; effectual agency.
The manner of this divine efficiency being far above us. Hooker. 2. 2. (Mech.) The ratio of useful work to energy expended. Rankine.
Efficiency of a heat engine, the ratio of the work done by an engine, to the work due to the heat supplied to it.