The words "affect" and "effect" are among the most commonly misused words in the English language.

Both can be used as either a ​noun​ or a ​verb​, but ​affect​ and ​effect​ are not interchangeable because the words have different meanings. To use affect and effect correctly, you must know each definition.

What Does Effect Mean?

as a ​noun​:

Use "effect" as a noun when you mean a change or result or the way something acts upon something else.

  • a phenomenon that follows and is caused by some previous phenomenon.
  • an outward appearance
  • an impression (especially one that is artificial or contrived).
  • (of a law) having legal validity
  • a symptom caused by an illness or a drug

as a ​verb​:

  • produce.
  • act so as to bring into existence
  • the central meaning or theme of a speech or literary work

How to Use Effect in a Sentence

Note the subtle difference in the use of ​effect​ as a verb, which means to cause something to happen or to bring about a result.

Substitute the words "bring about" to see if you are using ​effect​ as a ​verb​ correctly.

For example:

  • The stimulus checks are designed to ​effect​ a better economic status for the country.


  • The stimulus checks are designed to ​bring about​ a better economic status for the country.

Example sentences using effect:

  • Noun: The change in weather was an effect of global warming.
  • Noun: Global warming has a detrimental effect on the weather.
  • Noun: Hyperbole is an overstatement or exaggeration of speech for an effect.
  • Verb: Protesters want to effect change in government handling of clean-up.

I love that feeling of being in love, the effect of having butterflies when you wake up in the morning. That is special. - Jennifer Aniston

What Does Affect Mean?

As a ​noun​:

Define ​affect​ as a noun when you work in a medical or social service field.

As a noun, the word describes an aspect of behavior, or the way emotion relates to cognitive thinking.

For example:

Though the patient is coherent and oriented, his affect is inappropriately flat.

As a ​verb​:

Affect​ means to have an influence on or to produce a change. The verb ​Affect​ is used to show the noun acts upon the object. From the dictionary definitions at, Affect means:

  • to have an effect upon.
  • to act physically on
  • make believe with the intent to deceive
  • connect closely and often incriminatingly
  • have an emotional or cognitive impact upon

For example:

Canines, like people, can have allergies and experience allergic reactions that sometimes ​affect​ their ears.

How to Use Affect in a Sentence

Choose "affect" in most sentences requiring a verb.

Substitute the word "influence" or "change" to test if your choice makes sense:

  • "influence" or
  • "change"

For example:

  • "We want to see whether driving in the dark ​affects​ safety." vs.
  • "We want to see whether driving in the dark ​influences​ safety."

Affect vs. Effect: Tips to Choose the Right Word

For the most part, that you can use ​effect​ as a noun and ​affect​ as a verb.

  • When something is caused by, use ​effect.​ Think cause and effect.
  • When something will alter, change, or influence something else, use ​affect​. For example, Not requiring test scores for college applicants will affect the number of high school test takers.

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