efficiency

noun

ef·​fi·​cien·​cy i-ˈfi-shən-sē 

plural efficiencies

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

Synonyms

• edge
• effectiveness
• effectualness
• efficaciousness
• efficacity
• efficacy
• productiveness

Examples of efficiency in a Sentence

Because of her efficiency, we got all the work done in a few hours.

The factory was operating at peak efficiency.

A furnace with 80 percent fuel efficiency wastes 20 percent of its fuel.

The company is trying to lower costs and improve efficiencies.

Recent Examples on the Web

By meticulously executing each phase, organizations can optimize operational efficiency, drive innovation and enhance service delivery. —Vishal Dugar, Forbes.com, 3 Apr. 2025

Intelligence agencies need reform, but simply eliminating offices involved with DEI and declaring it a victory for efficiency would miss the point. —Joshua Yaphe, National Review, 3 Apr. 2025

Thanks to the President’s refocus of the agency, the Institute of Museum and Library Services will be able to better showcase American exceptionalism with greater efficiency for the public. —Sarah D. Wire, USA Today, 3 Apr. 2025

Those looking for a reliable option for consistent use will appreciate the efficiency and thoughtful features that this model offers. —Jordan Liberty Phillips, Better Homes & Gardens, 3 Apr. 2025

Word History

Etymology

borrowed from Latin efficientia, from efficient-, efficiens "producing or giving rise to something, immediate (of a cause), efficient" + -ia -y entry 2

First Known Use

1633, in the meaning defined at sense 1

Phrases Containing efficiency

• efficiency apartment
• efficiency expert
• hyper-efficiency

Rhymes for efficiency

• deficiency
• proficiency
• sufficiency
• immunodeficiency
• inefficiency
• insufficiency

Kids Definition

efficiency

noun

ef·​fi·​cien·​cy i-ˈfish-ən-sē 

plural efficiencies

1

: the quality or degree of being efficient

2

: efficient operation

3

: the ratio of the useful energy delivered by a machine to the energy supplied to it