ef·​fi·​cien·​cy | \ i-ˈfi-shən-sē How to pronounce efficiency (audio) \
plural efficiencies

Definition of efficiency

1 : the quality or degree of being efficient
2a : 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

Keep scrolling for more

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.
See More

Recent Examples on the Web

There is an efficiency in the game design that makes Gato Roboto feel concentrated. Michael Moore, The Verge, "Gato Roboto is a streamlined Metroid starring a cat in a mech," 30 June 2019 Cuomo’s appointees have claimed that the gas pipelines will cause environmental harm and that the state can replace natural gas with efficiency and renewable energy. Robert Bryce, National Review, "Cuomo’s Silly War on Natural Gas," 28 June 2019 And having someone to share the late-game play-making and scoring load would help Walker play with greater efficiency. Matt Eppers, USA TODAY, "NBA free agency: Kemba Walker's top five landing spots," 27 June 2019 With most of the limelight so far being shone on a free-scoring US side, Germany has gone about its business with quiet efficiency in France. George Ramsay, CNN, "Women's World Cup: Quarterfinals set to be 'wild and crazy'," 26 June 2019 Running the pick-and-roll with a deadly efficiency, the pair averaged 36.9 points this season, the highest combined scoring average of any reserve duo in NBA history. Andrew Greif, latimes.com, "NBA Awards: Clippers’ Lou Williams wins Sixth Man; Antetokounmpo earns MVP," 24 June 2019 The goal of automation has always been efficiency, but in this new kind of workplace, A.I. sees humanity itself as the thing to be optimized. Kevin Roose, New York Times, "A.I. May Not Take Your Job, but It Could Become Your Boss," 23 June 2019 Over time, with stealth and damning efficiency, this kind of toxic stress can take a toll on the body and mind. Jenny Anderson, Quartz, "The scientific effort to protect babies from trauma before it happens," 22 June 2019 His weakness, however, was efficiency: his huge aerobic engine provided him with lots of energy to burn, but that didn’t translate to otherworldly power outputs on the bike. Alex Hutchinson, Outside Online, "The Story of the Cyclist with the Highest-Ever VO2max," 20 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'efficiency.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of efficiency

1633, in the meaning defined at sense 1

History and Etymology for efficiency

borrowed from Latin efficientia, from efficient-, efficiens "producing or giving rise to something, immediate (of a cause), efficient" + -ia -y entry 2

Keep scrolling for more

Learn More about efficiency

Statistics for efficiency

Last Updated

4 Jul 2019

Look-up Popularity

Time Traveler for efficiency

The first known use of efficiency was in 1633

See more words from the same year

Keep scrolling for more

More Definitions for efficiency



English Language Learners Definition of efficiency

: the ability to do something or produce something without wasting materials, time, or energy : the quality or degree of being efficient


ef·​fi·​cien·​cy | \ i-ˈfi-shən-sē How to pronounce efficiency (audio) \
plural efficiencies

Kids Definition of efficiency

: the ability to do something or produce something without waste

Keep scrolling for more

Comments on efficiency

What made you want to look up efficiency? Please tell us where you read or heard it (including the quote, if possible).


providing supplementary assistance

Get Word of the Day daily email!

Test Your Vocabulary

Farm Idioms Quiz

  • cow coming home
  • What does 'poke' refer to in the expression 'pig in a poke'?
True or False

Test your knowledge - and maybe learn something along the way.

Syn City

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!