The meaning of EFFICACY is the power to produce a result or effect. How to use efficacy in a sentence.

EFFICACY definition: the capacity for producing a desired result or effect. See examples of efficacy used in a sentence.

EFFICACY meaning: 1. the ability of something to produce the intended result: 2. how well a particular treatment or…. Learn more.

Define efficacy. efficacy synonyms, efficacy pronunciation, efficacy translation, English dictionary definition of efficacy. n. Power or capacity to produce a desired effect; effectiveness. American …

If you talk about the efficacy of something, you are talking about its effectiveness and its ability to do what it is supposed to.

Definition of efficacy noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Dec 11, 2025 · Efficacy refers to the beneficial effects of a program or policy under optimal conditions of delivery, whereas effectiveness refers to effects of a program or policy under more real-world …

What does the noun efficacy mean? There are four meanings listed in OED's entry for the noun efficacy, three of which are labelled obsolete. See ‘Meaning & use’ for definitions, usage, and quotation …

Collins Concise English Dictionary © HarperCollins Publishers:: efficacy /ˈɛfɪkəsɪ/, efficaciousness /ˌɛfɪˈkeɪʃəsnəs/ n the quality of being successful in producing an intended result; effectiveness ' …

The effectiveness, or efficacy, of something is how well it works or brings the results you hoped for. A scientist does research to determine the efficacy of a vaccine or medicine under development.