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Word of the Day: Efficacy
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Word of the Day: Efficacy

Jul 26, 2026
07:25 pm

What's the story

"Efficacy" is a noun that refers to the ability of something to produce the desired or intended result. It is commonly used when discussing the effectiveness of medicines, treatments, policies, methods, or products. The word focuses on how well something performs its intended purpose.

Origin 

Origin of the word

"Efficacy" comes from the Latin word efficacia, meaning "effectiveness" or "power to produce results."

It entered English in the 16th century and has since been widely used in scientific, medical, and academic contexts to describe successful outcomes.

Synonyms 

Synonyms for 'efficacy'

Some common synonyms for "efficacy" include effectiveness, efficiency, potency, capability, success, usefulness, performance, competence, strength and ability.

These words all relate to achieving a desired result, although each may be used in different contexts.

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Sentence 

Sentence usage

Here's how "efficacy" can be used in sentences:

"Researchers tested the efficacy of the new vaccine in clinical trials."

"The study evaluated the efficacy of different teaching methods."

"Customers were impressed by the efficacy of the cleaning solution."

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Writing

Why use the word

If you want to highlight the effectiveness of an idea, product, or solution, "efficacy" is a strong word to use.

It is widely recognized in academic and professional writing and helps communicate results in a clear and meaningful way.

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