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operation - definition and synonyms


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noun operation pronunciation in American English /ˌɑpəˈreɪʃ(ə)n/
Word Forms
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  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.
    Undercover operations led to the arrest of the gang.
    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 someones 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. 5
    [countable] a company, or a part of a large company
    The company has recently expanded its international operation.
    The group is selling its overseas operations.
  6. 6
    [uncountable] the process of controlling something or of making it work
    Operation of this equipment requires special training.



a course of study which is much shorter than a university course and focuses on the skills you need for a job, especially computer-related skills

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an ancient Roman system of underfloor heating, used to heat houses with hot air; from the Latin 'hypocaustum'

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