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efficacy

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noun ef·fi·ca·cy \ˈe-fi-kə-sē\

Simple Definition of efficacy

  • : the power to produce a desired result or effect

Source: Merriam-Webster's Learner's Dictionary

Full Definition of efficacy

plural

efficacies

  1. :  the power to produce an effect

Examples of efficacy in a sentence

  1. In the planner's view, Rumsfeld had two goals: to demonstrate the efficacy of precision bombing and to “do the war on the cheap.” —Seymour M. Hersh, New Yorker, 7 Apr. 2003

  2. Vaccines exist, but their efficacy against aerosolized plague is unknown. —Sharon Begley et al., Newsweek, 8 Oct. 2001

  3. efficacy does not have to be demonstrated before homeopathic products are marketed. —Alison Abbott et al., Nature, 26 Sept. 1996

  4. <questioned the efficacy of the alarms in actually preventing auto theft>



Origin and Etymology of efficacy

(see efficacious)


First Known Use: 13th century



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