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
Recently, researchers have made a major leap forward by engineering a novel cathode material that dramatically elevates performance, bringing us closer to practical, high-efficiency thermal energy systems.
—
Prabhat Ranjan Mishra, Interesting Engineering, 12 Jan. 2026
The goal, Calvo said, is to reduce water costs, improve efficiency and enhance public safety, as well as to assess whether transitioning from analog meters to smart meters could result in improvements.
—Verónica Egui Brito, Miami Herald, 12 Jan. 2026
Space Forge estimates that the improved efficiency of these semiconductors could enable reductions in the energy use of electronic devices by up to 60 percent.
—Tereza Pultarova, Space.com, 11 Jan. 2026
Fuel efficiency was calculated at each wind speed and factored into our test score.
—Adam Trenkamp, Outside, 11 Jan. 2026
See All Example Sentences for efficiency
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Prabhat Ranjan Mishra, Interesting Engineering, 12 Jan. 2026
The goal, Calvo said, is to reduce water costs, improve efficiency and enhance public safety, as well as to assess whether transitioning from analog meters to smart meters could result in improvements.
—Verónica Egui Brito, Miami Herald, 12 Jan. 2026
Space Forge estimates that the improved efficiency of these semiconductors could enable reductions in the energy use of electronic devices by up to 60 percent.
—Tereza Pultarova, Space.com, 11 Jan. 2026
Fuel efficiency was calculated at each wind speed and factored into our test score.
—Adam Trenkamp, Outside, 11 Jan. 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 13 Jan. 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
Love words? Need even more definitions?
Merriam-Webster unabridged
Share