'efficiency' definitions:

Definition of 'efficiency'

From: WordNet
noun
The ratio of the output to the input of any system
noun
Skillfulness in avoiding wasted time and effort; "she did the work with great efficiency" [ant: inefficiency]

Definition of 'efficiency'

From: GCIDE
  • efficience \ef*fi"cience\ ([e^]f*f[i^]sh"ens), efficiency \ef*fi"cien*cy\ ([e^]f*f[i^]sh"en*s[y^]), 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]

Definition of 'efficiency'

From: GCIDE
  • efficiency apartment \efficiency apartment\ 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]