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
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:
The companies said the venture supports Geely’s international expansion and advances Ford’s strategy of using partnerships to compete with speed, efficiency and scale in Europe.
From The Wall Street Journal ● Jul. 23, 2026
The shuttle greatly increases both the speed and efficiency of triplet energy transfer compared with a methylated analog that does not contain the proton shuttle.
From Science Daily ● Jul. 22, 2026
Chinese models also have an advantage over U.S. ones when it comes to costs, Arya said, pointing to efficiency in architecture and lower prices for physical infrastructure such as electricity, labor and land in China.
From MarketWatch ● Jul. 21, 2026
The head of Boeing's Commercial Airplanes division, Stephanie Pope, said that the order "reflects the strong demand we are seeing for the 737 MAX family's efficiency, reliability and versatility".
From Barron's ● Jul. 20, 2026
She turned to him with a face of composure and relief —the efficient and undramatic face which women achieve when they have nursing to do, or some other employment of efficiency.
From "The Once and Future King" by T. H. White
The company had software engineers shadow bankers for two weeks from 8:30 a.m. to midnight and catalog everything they did to find efficiencies.
From The Wall Street Journal ● Jul. 20, 2026
Unsurprisingly, both Larry and David Ellison are big fans of artificial intelligence, seeing it as a way to streamline their surveillance operations, and for what David Ellison euphemistically calls “cost efficiencies and synergies.”
From Salon ● Jul. 20, 2026
Hou drew comparisons to last year’s DeepSeek moment, which caused Nvidia and other chip stocks to tumble on fears that compute efficiencies would reduce demand for AI infrastructure.
From MarketWatch ● Jul. 17, 2026
Today's investment plan also relies on £10.7bn of "defence efficiencies" being found by 2030, with little detail about how that would be achieved.
From BBC ● Jun. 30, 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
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.
