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.
The efficiency comes from the engine mechanics itself – not a higher octane level. — David Goldman, CNN Money, 3 July 2026 That meant the design had to favor stability and efficiency, almost like a giant paper glider. — New Atlas, 3 July 2026 Customers need to understand how the feature solves a real challenge, improves efficiency, reduces costs or enhances outcomes. — Expert Panel®, Forbes.com, 2 July 2026 The first factor is that efficiencies in health care, which translate to lower costs, also mean that societies are likely to live longer and will draw more heavily on social security support as a result. — Eleanor Pringle, Fortune, 2 July 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 9 Jul. 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

Nglish: Translation of efficiency for Spanish Speakers

Britannica.com: Encyclopedia article about efficiency

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