Did you know?

Click any word in a definition or example to find the entry for that word

effect - definition and synonyms


What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.



Thesaurus diagram

The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.

noun     effect pronunciation in British English
Word Forms
  1. 1
    [countable/uncountable] a change that is produced in one person or thing by another
    effect on/upon:

    Scientists are studying the chemical’s effect on the environment.

    have an effect on something:

    Any change in lifestyle will have an effect on your health.

    have some/little/no effect:

    The NAFTA agreement has had little effect on the lives of most Americans.

    an adverse/beneficial effect (=a bad/good effect):

    East German companies were suffering the adverse effects of German economic union.

    reduce/counter the effect(s) of something:

    Relaxation can reduce the negative effects of stress on the immune system.

  2. 2
    [countable] an appearance or reaction that is deliberately produced, for example by a writer, artist, or musician

    The bold colours in this room create a dramatic effect.

    That’s exactly the effect I wanted.

    get/produce/achieve an effect:

    Students should learn how they can achieve different stylistic effects in their writing.

    1. a.


      [plural] cinema special artificial images and sounds created for a film

      I didn’t think much of the plot, but the effects were amazing.

    2. b.
      [countable] [usually singular] an artificial appearance given to a surface or to an object

      marble-effect wallpaper

  3. 3
    [countable] [usually singular] something that regularly happens, according to a law, for example in science

    the Doppler effect

    what economists call ‘the multiplier effect’

  4. 4



    personal effects

    [plural] formal the things that belong to you
quiz invitation
  • Facebook
  • Twitter


a description of an economic or political situation based on analysis of information at the present time

BuzzWord Article

Open Dictionary


an unregulated form of capitalism that features financial deregulation, privatisation and low tax for high earners

add a word


A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog
Macmillan learn live love play