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

Back to the Bricks aims to introduce affordable models, improve dealer health, win market share, and improve operational efficiency.

From Barron's • May 5, 2026

Consumers buy vehicles for more than just efficiency, and when prices are lower, other vehicle attributes tend to dominate consumer choice, he said.

From MarketWatch • May 5, 2026

While cost-saving actions and broader efficiency initiatives are expected to position Norwegian Cruise Line for stronger performance over time, the company said the war in the Middle East is currently disrupting operations.

From The Wall Street Journal • May 4, 2026

Their goals include boosting energy efficiency and enabling continuous industrial operation over the coming decades.

From Science Daily • May 4, 2026

“For scientific discovery, give me Scott; for speed and efficiency of travel, give me Amundsen; but when disaster strikes and all hope is gone, get down on your knees and pray for Shackleton.”

From "Shipwreck at the Bottom of the World" by Jennifer Armstrong

Related Words

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