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.
Pill said improving the efficiency of the Welsh economy is the key to raising living standards.
From BBC • Jul. 9, 2026
COGE’s deregulation and government efficiency agenda is promising.
From The Wall Street Journal • Jul. 8, 2026
Her leadership style — she likes efficiency and structure — and interest in implementing some changes quickly turns heads at Pittsburgh Trauma Medical Center.
From Los Angeles Times • Jul. 8, 2026
The spokesperson did not comment on whether it was specifically call-center employees whose roles were being eliminated, but highlighted the efficiency of its AI agent that provides roadside assistance in multiple languages around the clock.
From MarketWatch • Jul. 8, 2026
The new isotope’s potency and the efficiency of the cyclotron in producing it surprised even experts accustomed to Lawrence’s guileless optimism.
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.
