extension - definition and synonyms


Your browser doesn’t support HTML5 audio

  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. 4
    [countable] something that you add to a long thin object to make it able to reach somewhere

    This lead isn’t long enough – do you have an extension?

    1. a.


      [plural] long pieces of artificial hair that can be fastened to someone’s hair to make it look longer
  5. 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.

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

    His leg was now capable of full extension.

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

    the further extension of state control

  8. 8
    [countable] computing the last part of the name of a computer file. For example, ‘exe’ and ‘doc’ are extensions.
  9. 9
    [uncountable] in the UK, a system in which students can take courses at a university without being full-time students

    courses provided through university extension