Affect vs. effect is confusing because both words can be used a both nouns and verbs! However, some of those uses are rare.

Most commonly:

Affect is a VERB, as in, “That movie really AFFECTED me.”

Effect is a NOUN, as in, “The treatment has some side EFFECTS.”

Much less commonly…

Affect as a noun is a term in psychology (“the emotion associated with an idea”), but you will probably never hear this.

Effect as a verb is more interesting — it means to bring about, to cause to occur.

Confused by Affect vs. Effect? Teach yourself the difference on the Manhattan Prep blog!