Affect and effect are consistently among the most frequently looked up terms at Dictionary.com. The perennial interest is not surprising: both of these words can be used as verbs and nouns, and their meanings overlap thematically. This slippery duo can send even experienced writers into a spiral of uncertainty.
Much of the confusion surrounding this pair is due to a shared linguistic ancestor: both words have roots in the Latin verb facere meaning “to do, make.” Affect derives from the Latin verb afficere meaning “to do something to, to have influence on.” Effect descends from the Latin verb efficere, “to make, carry out.”
When it comes to determining which of these to use in a given sentence, it’s helpful to remember that one of these words is more commonly used as a verb, and the other a noun. The verb affect means “to act on; produce an effect or change in” as in The cold weather affected the crops. It can also mean “to impress the mind or move the feelings of,” as in The music affected him deeply. When you’re looking to use one of these two terms to express an action, chances are you’re after affect rather than effect.
Effect is most commonly used as a noun meaning “result” or “consequence,” as in Exposure to the sun had the effect of toughening his skin. It can be used as a verb to mean “make happen,” but that use is less common. Sticking to the basic guideline of effect as a noun and affect as a verb will generally keep you in the good graces of your readers.
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