effective

Definition

Having the power to produce a required effect or effects.

Etymology

From French effectif, from Latin effectīvus (“productive; effective”), from efficiō (“I make; I bring about”), equivalent to effect + -ive.

Example Sentences

• "The pill is an effective method of birth control."
• "Fire ants circumvented the problem of an ineffective sting by having an unusual and highly effective venom that when daubed or sprayed on other ants penetrates their waxy protective integumental barrier and kills or disables them."
• "The president delivered an effective speech!"

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