efficiency

noun

ef·​fi·​cien·​cy i-ˈfi-shən-sē How to pronounce efficiency (audio)
plural efficiencies
Synonyms of efficiency
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 of efficiency

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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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
These chemical conflicts ultimately leave current flexible solar modules far behind their rigid counterparts in both efficiency and stability. — Mrigakshi Dixit, Interesting Engineering, 26 Oct. 2026 The longer-term outcome of the new approach, the agency hopes, will reduce the financial and technical burden on competing research teams and ultimately get missions from idea to orbit with efficiency and speed. — Josh Dinner, Space.com, 26 Oct. 2026 Gabriel, however, is more skeptical, arguing that infrastructure carries the incentives of the model that built it, making a brand with less influence likely to struggle to resist a parent company oriented around speed, efficiency, and growth. — Jessica Binns, Vogue, 26 Oct. 2026 For productions, that means campus efficiency paired with location diversity, all a short flight from both coasts. — Partner Content, Variety, 26 Oct. 2026 See All Example Sentences for efficiency

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

Time Traveler
The first known use of efficiency was in 1633

Phrases Containing efficiency

Rhymes for efficiency

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Browse Nearby Words

efficience
efficiency
efficiency apartment
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Cite this Entry

“Efficiency.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/efficiency. Accessed 27 Oct. 2026.

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Kids Definition

efficiency

noun
ef·​fi·​cien·​cy i-ˈfish-ən-sē How to pronounce efficiency (audio)
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

More from Merriam-Webster on efficiency

Britannica.com: Encyclopedia article about efficiency

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