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

But don’t let its lightweight design fool you — tons of reviewers have raved about its efficiency. —Clara McMahon, People.com, 27 Apr. 2025

Governments Must Strengthen Regulations For Phosphorus Efficiency The other side of tackling phosphorous overuse is improving its efficiency— and that is a problem that can be solved. —Simi Thambi​, Forbes.com, 26 Apr. 2025

But Soucek ranks high among Premier League midfielders for his offensive efficiency. —Roshane Thomas, New York Times, 26 Apr. 2025

Zorn and her team will advise family office clients on structure and design, family governance, operational efficiency, and board, leadership, philanthropic and human capital advisory. —Sportico Staff, Sportico.com, 25 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