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

The Knights struggled to maintain their early efficiency with Prince avoiding foul trouble in the second half. —Steven Johnson, Fort Worth Star-Telegram, 22 Mar. 2025

Programs such as Lean Six Sigma have been successfully implemented by many Fortune 500 companies to improve operational efficiency. —Chicago Tribune, 21 Mar. 2025

This significantly lowers the barrier for cyberattacks and increases the speed and efficiency of data theft—sometimes in minutes, before security teams even detect an intrusion. 3. —Keren Katz, Forbes, 21 Mar. 2025

Robert Morris shot just 42 percent, relying more on extra shots (78-58 advantage) rather than efficiency, and only managed eight free throws on 13 attempts (62%). —Thomas G. Moukawsher, Newsweek, 21 Mar. 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