efficiency
noun
ef·fi·cien·cy
i-ˈfi-shən-sē 
plural efficiencies
1
: the quality or degree of being efficient
2
a
: 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
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.
Recent Examples on the Web
For years, energy efficiency programs disproportionately benefited wealthier homeowners — those with the time, capital, and access to take advantage of rebates, upgrades, and incentives.
—
Ed Gaskin, Boston Herald, 26 Apr. 2026
Denver’s 3-point efficiency — the highest in the league during the regular season — completely plummeted, again.
—Bennett Durando, Denver Post, 26 Apr. 2026
The quiet efficiency that underlies everything tends to preserve energy levels, which is a critical, albeit understated ingredient in Emery’s success in European competitions throughout his managerial career.
—Jacob Tanswell, New York Times, 26 Apr. 2026
DeepSeek’s earlier flagship system supported up to 128,000 tokens, but the new architecture significantly expands that capacity while improving efficiency.
—Bojan Stojkovski, Interesting Engineering, 26 Apr. 2026
See All Example Sentences for efficiency
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Ed Gaskin, Boston Herald, 26 Apr. 2026
Denver’s 3-point efficiency — the highest in the league during the regular season — completely plummeted, again.
—Bennett Durando, Denver Post, 26 Apr. 2026
The quiet efficiency that underlies everything tends to preserve energy levels, which is a critical, albeit understated ingredient in Emery’s success in European competitions throughout his managerial career.
—Jacob Tanswell, New York Times, 26 Apr. 2026
DeepSeek’s earlier flagship system supported up to 128,000 tokens, but the new architecture significantly expands that capacity while improving efficiency.
—Bojan Stojkovski, Interesting Engineering, 26 Apr. 2026
See All Example Sentences for efficiency
Cite this Entry
“Efficiency.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/efficiency. Accessed 1 May. 2026.
Copy CitationKids Definition
efficiency
noun
ef·fi·cien·cy
i-ˈfish-ən-sē
plural efficiencies
1
: the quality or degree of being efficient
2
: efficient operation
3
: the ratio of the useful energy delivered by a machine to the energy supplied to it
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