Definition:

It's not that people don't know what these words mean; it's that they have trouble remembering which one does what. The simplest distinction here is that affect is almost always a verb, and effect is usually a noun.

These words are frequently confused in part because their meanings are related. For more information, please see our Ask the Editor video.

Example:

"Lithium, after all, can be toxic, and though the levels in the Oita study are too low to have an immediate effect, the element can affect kidney function and cause long-term health problems." – Clay Risen, The New York Times Magazine, December 13, 2009