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

Definition of efficiency

1 : the quality or degree of being efficient
2a : 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

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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.
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Recent Examples on the Web

There's tremendous potential for efficiencies in the large-scale application of mechanization, fertilization, and pesticide use. John Timmer, Ars Technica, "Urban farms could be incredibly efficient—but aren’t yet," 27 Dec. 2018 And instead of gears, continuously variable transmissions use chains to provide an infinite number of ratios, allowing maximum efficiency in power delivery. Blake Z. Rong, Popular Mechanics, "10 Innovations That Made the Modern Car," 4 Dec. 2018 Architects need to do their piece to maximize energy efficiency in new buildings, commercial and industrial as well as residential. Gaby Del Valle, Vox, "Can consumer choices ward off the worst effects of climate change? An expert explains.," 12 Oct. 2018 What’s happened is that, over the last decade, the cost and the energy efficiency in batteries have improved through iteration in the manufacturing process. Michael Zelenko, The Verge, "The US is losing the high-stakes global battery war," 13 Aug. 2018 African Parks assumes day-to-day management of countries’ wildlife areas, seeking more efficiency and accountability in the campaign to protect flora and fauna from poaching and habitat depletion. Washington Post, "Backed by Prince Harry, conservation group expands in Africa," 7 July 2018 In Germany, Deutsche Bahn, the state rail giant, once looked up to as a paragon of quality and efficiency in Europe, is increasingly under attack in the country’s press for its dirty, late trains. The Economist, "European state rail firms face scrappy new competitors," 28 June 2018 Even with the prospect of selling its retail arm, Overstock continues to invest in its e-commerce efforts, including working on efficiency in its supply chain and adding a new distribution center to improve its two-day shipping. New York Times, "From Furniture to Cryptocurrency — Overstock Is on a Journey," 27 June 2018 Some of that bounty will come from the reduction in human headcount, but far more will come from enormous efficiencies in matching product to customer, drug to patient, solution to problem. Jonathan Vanian, Fortune, "Unmasking A.I.'s Bias Problem," 25 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'efficiency.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of efficiency

1633, in the meaning defined at sense 1

History and Etymology for efficiency

borrowed from Latin efficientia, from efficient-, efficiens "producing or giving rise to something, immediate (of a cause), efficient" + -ia -y entry 2

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Last Updated

14 Mar 2019

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Time Traveler for efficiency

The first known use of efficiency was in 1633

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English Language Learners Definition of efficiency

: the ability to do something or produce something without wasting materials, time, or energy : the quality or degree of being efficient


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

Kids Definition of efficiency

: the ability to do something or produce something without waste

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Comments on efficiency

What made you want to look up efficiency? Please tell us where you read or heard it (including the quote, if possible).


to corrupt or become corrupted

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