%efficiency%

{ } n. [ L. efficientia. ] 1. 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. Hooker. [ 1913 Webster ]

2. (Mech.) 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. [ 1913 Webster ]

n., a small apartment{ 4 }, sometimes furnished, with minimal kitchen and bath facilities. The unit may comprise a single room plus a bathroom, and the kitchen facilities are often open to the main room, or may form a small niche in a corner. There are many variations of efficiency apartment, including some in which furnishings such as a bed may be pulled out from a wall recess and stored there again when not in use. Also called an efficiency. [ PJC ]