Main Entry: ef·fi·cien·cy

Pronunciation: \i-ˈfi-shən-sē\

Function: noun

Inflected Form(s): plural ef·fi·cien·cies

Date: 1633

1 : the quality or degree of being efficient
2 a : efficient operation b (1) : effective operation as measured by a comparison of production with cost (as in energy, time, and money) (2) : the ratio of the useful energy delivered by a dynamic system to the energy supplied to it
3 : efficiency apartment