Part of speech: noun
Origin: Latin, 16th century
The ability to produce a desired or intended result.
Examples of Efficacy in a sentence
"For the greatest efficacy, take this medication before meals."
"John proved the efficacy of his intense study regimen with the high marks he received."
“Efficacy” is based on the Latin “efficācia,” meaning “potential to accomplish.”
Did you Know?
“Efficacy” is easily confused with “efficiency,” but the meanings of the two words come from different Latin roots. “Efficacy,” like “effectiveness,” describes a capacity for achievement. It's roughly a direct translation of its Latin root “efficācia.” On the other hand, “efficiency” means the ability to maximize productivity while minimizing effort or expense. It is based on the Latin “efficientia,” meaning “efficient power.”