Affect is both a noun and a verb, but the verb is far more common; it means "to act on or change someone or something," as in "The change will affect everyone."

AFFECT definition: to act on; produce an effect or change in. See examples of affect used in a sentence.

AFFECT definition: 1. to have an influence on someone or something, or to cause a change in someone or something: 2…. Learn more.

Affect means to bring about a change, to move emotionally, or to infect, as a disease. Its core meaning is to evoke a usually strong mental or emotional response from.

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

Affect and effect are two of the most commonly confused words in English, but don’t worry—we’ll help you keep them straight. The basic difference is this: affect is usually a verb, and effect is usually a noun.

Affect1 and effect, each both noun and verb, share the sense of "influence,'' and because of their similarity in pronunciation are sometimes confused in writing.

Affect is most often used as a verb meaning “to have an impact on,” as in “The tornado barreling towards us will affect our picnic plans.”

Jan 17, 2026 · affect (third-person singular simple present affects, present participle affecting, simple past and past participle affected) (transitive) To influence or alter.

Affect is a psychological term that describes observable emotional responses or feelings, which can be seen through a person's facial expressions, voice tone, body language, or behavior.