efficiency B1 Topic:Numbers & Quantity US /ɪˈfɪʃ.ən.si/ See IPA manual Freq #10945 Meanings 1 noun The quality of doing something well without wasting time, effort, or money. They did the work with great efficiency. 2 noun The ratio of useful output to the energy or resources used. The new engine improves fuel efficiency by twenty percent. Thesaurus Word family Forms efficienciesinefficiency Derived forms coefficiencyecoefficiencyequiefficiencyhigh-efficiencylow-efficiencynonefficiencyphotoefficiencysuperefficiency Related forms effecteffectiveeffectivenesseffectivityeffectoreffectualeffectuateefficaciousefficacityefficacyefficientefficiently Common collocations energy efficiency Noun + noun propulsive efficiency Adjective + noun Etymology AI details From Latin efficientia, equivalent to efficient + -cy. Topics Numbers & Quantity External links Cambridge Dictionary Wiktionary Google Images # efficiency **Type:** Word **Level:** B1 **Part of speech:** noun **IPA (US):** /ɪˈfɪʃ.ən.si/ **Frequency rank:** 10945 ## Meanings 1. The quality of doing something well without wasting time, effort, or money. 2. The ratio of useful output to the energy or resources used. ## Examples - They did the work with great efficiency. - The new engine improves fuel efficiency by twenty percent. ## Derived Forms - coefficiency - ecoefficiency - equiefficiency - high-efficiency - low-efficiency - nonefficiency - photoefficiency - superefficiency ## Related Forms - effect - effective - effectiveness - effectivity - effector - effectual - effectuate - efficacious - efficacity - efficacy - efficient - efficiently ## Etymology From Latin efficientia, equivalent to efficient + -cy. ## AI Etymology Efficiency comes from Latin efficientia, equivalent to efficient + -cy. In current use, the main senses are “The quality of doing something well without wasting time, effort, or money” and “The ratio of useful output to the energy or resources used”. ## Topics - Numbers & Quantity markdown