efficiency

American  

[ih-fish-uhn-see] / ɪˈfɪʃ ən si /

noun

plural

efficiencies

1. the state or quality of being efficient, or able to accomplish something with the least waste of time and effort; competency in performance.

2. accomplishment of or ability to accomplish a job with a minimum expenditure of time and effort.

   The assembly line increased industry's efficiency.

3. 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.

4. efficiency apartment.

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efficiency British  

/ ɪˈfɪʃənsɪ /

noun

1. the quality or state of being efficient; competence; effectiveness

2. 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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efficiency Scientific  

/ ĭ-fĭsh′ən-sē /

1. 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.

2. See also mechanical advantage

3. The ratio of the effective or useful output to the total input in any system.

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Other Word Forms

• nonefficiency
  noun
• superefficiency
  noun

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.

Example Sentences

Josh Gruenbaum, a senior GSA acquisitions official recruited through Musk’s Department of Government Efficiency, assured government officials that the government platform of Grok was separate from the public one.

From The Wall Street Journal • Feb. 27, 2026

I talked with Uber and taxi drivers who are suffering because of all the Department of Government Efficiency firings.

From Salon • Feb. 13, 2026

Reform made quite a big deal of setting up its own version last year of Donald Trump's Doge - the Department of Government Efficiency - with Yusuf leading it until recently.

From BBC • Feb. 4, 2026

The stock has been under pressure because of efforts to reduce government waste, including actions taken by the Department of Government Efficiency.

From Barron's • Jan. 26, 2026

White had to constantly fill out Efficiency Rating sheets, grading agents, on a scale of 0 to 100, in such categories as “knowledge,” “judgment,” “personal appearance,” “paper work,” and “loyalty.”

From "Killers of the Flower Moon" by David Grann

Related Words

• ability
• adaptability
• capability
• competence
• energy
• expertise
• performance
• productivity
• readiness
• skill
• talent