efficiency
Americannoun
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the state or quality of being efficient, or able to accomplish something with the least waste of time and effort; competency in performance.
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accomplishment of or ability to accomplish a job with a minimum expenditure of time and effort.
The assembly line increased industry's efficiency.
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the ratio of the work done or energy developed by a machine, engine, etc., to the energy supplied to it, usually expressed as a percentage.
noun
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the quality or state of being efficient; competence; effectiveness
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the ratio of the useful work done by a machine, engine, device, etc, to the energy supplied to it, often expressed as a percentage See also thermal efficiency
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The ratio of the energy delivered (or work done) by a machine to the energy needed (or work required) in operating the machine. The efficiency of any machine is always less than one due to forces such as friction that use up energy unproductively.
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See also mechanical advantage
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The ratio of the effective or useful output to the total input in any system.
Other Word Forms
Etymology
Origin of efficiency
First recorded in 1585–95; from Latin efficientia, from efficient- (stem of efficiēns efficient ) + -ia -y 3
Explanation
Efficiency is avoiding a waste of time, effort, or resources. Many people have begun to use compact fluorescent light bulbs because of their greater energy efficiency. Nowadays, efficiency often refers to energy efficiency, the effort to get more energy from existing resources: making cars that can go farther with less fuel, or appliances that do the same work with less electricity. But this noun isn't restricted to an environmental context. Efficiency can also simply be a measurement of what goes into a thing versus what comes out of it. A process with high efficiency requires only a little work to produce big results.
Vocabulary lists containing efficiency
Word Generation Science - Energy
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"The Veldt" by Ray Bradbury
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The Boy in the Striped Pajamas
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
He noted that the MWD invests in water efficiency and capturing stormwater, and has helped reduce per-person water use by more than 40% since 1990.
From Los Angeles Times • May 25, 2026
Montpellier did not just break Ulster's hearts but shattered them with a display of ruthless efficiency to win the competition for a third time, impressive 59-26 victors.
From BBC • May 22, 2026
Or he can push for a rate cut to keep credit flowing and let high prices call forth new supply, substitution and efficiency.
From MarketWatch • May 22, 2026
Stronger stewardship and listed companies’ shift toward greater capital efficiency, shareholder returns and optimal leverage should lift their price-to-earnings and price-to-book multiples.
From The Wall Street Journal • May 21, 2026
The White House, one learns, operates with the express purpose of optimizing the well-being, efficiency, and overall power of one person—and that’s the president.
From "Becoming" by Michelle Obama
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
