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# efficiency

noun (efficiency, efficiencies — rare plural)

«efficiency» in the English dictionary: everyday — its meanings, how the lessons use it, and examples, each with its tree on Mova.

## Everyday

1. Efficiency is doing a job well without wasting time, energy, money or materials. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#m1)
2. In science, efficiency is how much of the energy you put into a machine turns into useful work, often given as a percentage. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#m2)
3. (US) An efficiency is a very small flat or apartment with one main room. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#m3)

### In the lessons

In science lessons a light bulb with high efficiency turns more electricity into light and less into heat; efficiency = useful energy out ÷ total energy in × 100%. In everyday life people praise a shop or a team for its efficiency, and appliances have energy efficiency labels. Phrases: energy efficiency, fuel efficiency, with great efficiency, improve efficiency.

### Examples

- The new boiler has much better efficiency than the old one. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#x1)
- She cleaned the kitchen with amazing efficiency. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#x2)
- LED bulbs have a higher efficiency than old bulbs. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#x3)
- If 100 J go in and 25 J come out as light, the efficiency is 25%. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#x4)
- The fridge has an A energy efficiency label. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#x5)
- The team worked with speed and efficiency. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#x6)
- Fuel efficiency tells you how far a car goes on one litre. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#x7)
- Their landlord rents out an efficiency near the college. (US) [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/#x8)

### Note

Mostly uncountable: «efficiency», not «an efficiency» (except the US flat). The adjective is «efficient», the adverb «efficiently». Do not confuse with «effectiveness» (whether something works at all). In science, efficiency can never be more than 100%; a machine claiming more is a myth or a mistake.

## On Mova

- [Trees and pragmatics of «efficiency» in the school dictionary](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/efficiency/): every meaning and example parsed by Mova, with its dependency tree and frames.
- [«efficiency» in the school dictionary](https://mova.elamur.ai/free/en/dictionaries/school/w/efficiency.html) on Mova free.