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operation - definition and synonyms

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noun     operation pronunciation in American English
Word Forms
  1. 1
    [countable] a planned activity involving a lot of people, especially soldiers or police officers

    This was the biggest military operation in 20 years.

    rescue/relief/cleanup operation:

    The cleanup operation will take weeks.

  2. 2
    [countable] an action or set of actions that is necessary to achieve something

    Connecting the water supply is a very simple operation.

    The computer performs this operation many times every day.

  3. 3
    [countable] the process of cutting into someone’s body for medical reasons

    a stomach/heart operation

    have/undergo an operation:

    The baby had to have an operation, but he’s fine now.

    operation on:

    She may need an operation on her knee.

    do/perform/carry out an operation:

    A very experienced heart surgeon will perform the operation.

  4. 4
    [uncountable] the way that something such as a system or service operates

    We are visiting schools to explain the operation of the new exam system.

    1. a.
      used about the way that a machine or piece of equipment operates

      Something was interfering with the radar equipment’s operation.

    2. b.
      used about the way that something such as a rule or an idea is used

      Science investigates the operation of general laws.

  5. 6
    [uncountable] the process of controlling something or of making it work
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