efficience
efficience (ef*fish"ens) , noun
[Latin efficientia.]
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.
2.
(Mechanics) The ratio of useful work to energy expended. — Rankine
Collocations (1)
efficiency of a heat engine , the ratio of the work done by an engine, to the work due to the heat supplied to it.
Also: efficiency