efficiency

noun

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

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.
At the same time, niche and local players who master efficiency and identity—like Dragonfly and Goodlyfe—can still carve out major wins. Javier Hasse, Forbes.com, 26 June 2025 Arredondo is not alone in that sentiment as the legal profession, like so many other industries, tries to balance the efficiency gains offered by AI with safety. Jeff John Roberts, Fortune, 26 June 2025 At stake is not just economic efficiency, but the rule ... Iain Murray, National Review, 26 June 2025 These ambitions are not just about size and speed but also reflect efficiency and sustainability concerns for energy consumption and cooling. IEEE Spectrum, 26 June 2025 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

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Cite this Entry

“Efficiency.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/efficiency. Accessed 3 Jul. 2025.

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

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