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 Quarterbacks Cameron Teague Robinson: Finally healthy from a plethora of injuries dating back to fall camp, Micale Cunningham has an efficiency rating of 198.74, fourth nationally. Cameron Teague Robinson, The Courier-Journal, "Louisville vs. Kentucky: Here's who has the advantage at each position for Governor's Cup," 29 Nov. 2019 Rawlings ranks first in completions (583), pass attempts (926), completion percentage (.630), passing yards (7,638), passing touchdowns (60), efficiency rating (159.13), total yards (7,907) and total touchdowns (71). Edward Lee, baltimoresun.com, "As Kurt Rawlings set records at Yale, his mother battled breast cancer. But she never missed one of his games.," 28 Nov. 2019 His scoring, rebounding, assists and player efficiency rating are all up this season, but this isn't just a matter of volume. Ben Golliver, courant.com, "The Celtics are over Kyrie Irving and playing like a true contender," 27 Nov. 2019 Manny Wilkins’ successor ranks fourth in the Pac-12 with a 156.4 efficiency rating. Michael Lev, azcentral, "Arizona Wildcats brace for latest version of Arizona State's big three," 26 Nov. 2019 For one, while the region has high electric rates, its strong energy efficiency programs mean electric bills are well in line with the national average. Benjamin Storrow, Scientific American, "Cities Look to Natural Gas Bans to Curb Carbon Emissions," 25 Nov. 2019 Energy efficiency is about much more than lightbulbs. BostonGlobe.com, "Erika Niedowski: We must drastically reduce our reliance on fossil fuels in key sectors - The Boston Globe," 22 Nov. 2019 Jackson has passed for 19 TDs with just 5 interceptions through 10 games, while his 106.3 pass efficiency rating ranks among the top 5 in the league. Jarrett Bell, USA TODAY, "Opinion: Lamar Jackson's highlights have become NFL's must-see TV," 17 Nov. 2019 Thanks to improvements in energy-efficiency and tweaks to concrete mixtures, the average carbon dioxide intensity of cement production has decreased by 18% globally over the past 20 years. Marcello Rossi, Quartz, "Scientists are taking concrete steps towards reducing cement’s massive carbon footprint," 15 Nov. 2019

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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Time Traveler for efficiency

Time Traveler

The first known use of efficiency was in 1633

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Statistics for efficiency

Last Updated

5 Dec 2019

Cite this Entry

“Efficiency.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/efficiency. Accessed 11 December 2019.

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More Definitions for efficiency


How to pronounce efficiency (audio)

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).


heavy with or as if with moisture

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