Did you know?

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


 - definition

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.



The thesaurus of synonyms and related words is fully integrated into the dictionary entries. Click on the T button in an entry to review the synonyms and related words for that meaning.

noun extension pronunciation in British English /ɪkˈstenʃ(ə)n/ 
Word Forms

Related dictionary definitions

  1. 1
    [countable] an extra room or rooms added to a building

    We are building an extension on the back of our house.

    extension to:

    He has applied for permission to build a single-storey extension to his house.

  2. 2
    [countable] a telephone line that is one of several lines coming from a main line

    What's your extension?

    I'm on extension 334.

    a new extension number

  3. 3
    [countable] extra time that you are given to finish a piece of work, especially at college or university
    extension on:

    I'm going to ask for an extension on this essay.

    1. a.
      extra time that you are given to pay money that you owe
      extension on:

      Will the bank give you an extension on the loan?

    2. b.
      extra time that you are given to use a particular legal document or right

      a visa extension

      extension to:

      Brady wants a two-year extension to his contract.

    3. c.
      extra time that a shop, business, or bar is allowed to stay open

      There was a bar extension until midnight.

      extension to:

      Local shops have been granted an extension to opening hours.

  4. 5
    [countable] something that develops from a particular custom, activity, idea etc
    extension of:

    Business entertainment seems a natural extension of Japan's gift-giving culture.

    He sees local history as an extension of family history.

  5. 6
    [uncountable] formal the action of stretching part of your body

    His leg was now capable of full extension.

  6. 7
    [singular/uncountable] an increase in the power of something
    extension of:

    the further extension of state control


a paid holiday given to a new employee before they start their job

BuzzWord Article

Open Dictionary

selfie stick

an expandable stick which you attach to a mobile phone or camera to help you take a selfie …

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