

The verb effect means "to bring about or execute": medical treatment designed to effect a cure. Note that affect does not have a noun sense meaning "an influence that brings about a change." As a verb, affect is most commonly used in the sense of "to cause a change in:" the ways in which smoking affects health. As a noun it is uncommon and means roughly "emotion." It is pronounced with stress on the first syllable rather than the second. The other affect, the one that is confused with effect, is both a noun and a verb.

One means "to put on a false show of," as in She affected a British accent. First, bear in mind that there are two words spelled affect. Usage Note: Affect and effect are often confused because they sound alike and have related meanings.
