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

The need for efficiency is partly a function of the huge increase in applicants that many colleges have seen. Tyler Kingkade, Town & Country, "College Admissions Has a Fact-Checking Problem. Here's Why.," 24 Mar. 2019 The front air intake inside the corporate Audi grill is an active design that can close for better aero efficiency when needed. Jonathan M. Gitlin, Ars Technica, "We’ve driven Audi’s first proper electric car, the 2019 e-tron SUV," 7 Dec. 2018 The sedan still has stalks sticking out of its sides, but their lower-profile design reduces aerodynamic drag for fuel efficiency and cuts down on wind noise. Gary Gastelu, Fox News, "Don't look back: Lexus launching first digital side view mirrors," 12 Sep. 2018 Critics, though, have noted that rocketing troops into space, landing them and extracting them would require enormous amounts of fuel and the lightest ship possible for efficiency. Tom Vanden Brook, USA TODAY, "Jim Mattis once wanted to rocket Marines into space, foreshadowing Trump's Space Force," 11 July 2018 Above all, Mr Trump’s trade nationalists hate it that, in their search for efficiency, savings and speed, American businesses have internationalised their operations over the past four decades. The Economist, "Asia is at last waking up to the threat of a trade war," 28 June 2018 Modified intake ports and new, higher-pressure fuel injectors enhance fuel delivery to the cylinders and better atomize the gas for higher efficiency and torque. Jeff Yip, Houston Chronicle, "2019 Mazda MX-5 gets 26-hp boost," 23 June 2018 Everyday practices like recycling and decreased water usage, along with larger investments such as solar panels for energy efficiency, were part of the evaluation. Chuck Gibson, Cincinnati.com, "Catholic communities honored for ‘Care of Our Common Home’," 21 June 2018 Developments in jet design, like the push for fuel efficiency, meant more business for Rose, whose heavy-duty gears are specially heat-treated to stand up to increasingly powerful engines. Rebecca Lurye, courant.com, "Windsor's Aero Gear Expands, Adds New Hires," 13 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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Statistics for efficiency

Last Updated

11 Apr 2019

Look-up Popularity

Time Traveler for efficiency

The first known use of efficiency was in 1633

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More Definitions for efficiency



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).


marked by a state of overwhelming emotion

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