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Definitions

efficacy

[ef-i-kuh-see] / ˈɛf ɪ kə si /


Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

“There are scientific studies on the efficacy of different types of work that are adjacent to, or similar to what I do, but nothing exact.”

From Los Angeles Times • Apr. 22, 2026

Ideaya Biosciences surged 13% after the biotechnology company released positive, statistically significant results from a clinical trial evaluating the efficacy of a combination therapy in patients with a rare form of eye cancer.

From Barron's • Apr. 13, 2026

New research by the Protest Project, led by sociologists Dana Fisher and Arman Azedi, suggests that No Kings is having a positive effect on encouraging political engagement, efficacy and momentum among participants.

From Salon • Apr. 4, 2026

“The risk is that constant flip-flopping and headline fatigue is starting to seriously undermine the efficacy of the ‘Trump put,’” Barclays analysts said in an equity research note Friday.

From MarketWatch • Mar. 27, 2026

Three were scientists checking the efficacy of sprays; 8 worked in greenhouses; 5 were farm workers.

From "Silent Spring" by Rachel Carson




Vocabulary lists containing efficacy