efficiency
Americannoun
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efficiencies
plural
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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
Derived Forms
Inflected Forms
Nouns
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.
See Examples For:
Scientists have discovered that European nightjars sacrifice flight efficiency for agility and use an unexpected wingbeat technique previously associated mainly with bats and insects.
From Science Daily ● Oct. 17, 2026
Those figures cover more than AI, but they show the scale of the business and investment that efficiency improvements must support.
From MarketWatch ● Oct. 16, 2026
A landlocked country still widely associated with a horrific genocide in 1994, Rwanda has used sports to revamp its image, attract tourists and impress investors with its organisational efficiency.
From Barron's ● Oct. 16, 2026
They are also offering communities millions in local investments such as free community college and energy efficiency upgrades, and in some cases, pledging to give residents checks if data centers are built.
From The Wall Street Journal ● Oct. 15, 2026
They would find an apartment for rent: usually a studio, sometimes an efficiency, whatever they could afford and wherever they could go month to month, for Mia did not like to be tied down.
From "Little Fires Everywhere" by Celeste Ng
STOCKHOLM—Ericsson set out plans to streamline its operating structure, seeking to strengthen its customer focus and drive efficiencies while warning that higher component costs will be a headwind to profitability next year.
From The Wall Street Journal ● Oct. 15, 2026
"We are repositioning people from other units as we get the efficiencies to this and then that will let the head count drain down," he said.
From Barron's ● Oct. 14, 2026
"Justice delayed is justice denied, and I am committed to maximising efficiencies in our system alongside record investment. I remain committed to structural reform which is crucial if we are to bring down the backlog."
From BBC ● Oct. 4, 2026
Beyond the model layer, Microsoft is also investing in hardware efficiencies.
From MarketWatch ● Sep. 1, 2026
Having absorbed Lawrence’s confidence that further efficiencies eventually would be achieved, Groves reduced the specification for Y-12 to five hundred tanks, or five racetracks.
From "Big Science" by Michael Hiltzik
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Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
