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know - definition and synonyms


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verb [never progressive] know pronunciation in British English /nəʊ/
Word Forms
present tense
present participleknowing
past tenseknew
past participleknown
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  1. 1
    [intransitive/transitive] to have learned or found out about something
    ‘Have they arrived yet?’ ‘I don’t know.’
    If you don’t know the answer, just guess.
    How do you know my name?
    know (that): I knew she wasn’t really happy.
    know what/where/how etc: I don’t know where the money’s coming from.
    know if: I need to know if she’s made a decision yet.
    know something about someone/something: I don’t know anything about it.
    know something for sure/for certain/for a fact: We know for a fact that the fire was started deliberately.
    know something from experience: We know from experience that unemployment makes the problem worse.
    1. a.
      [intransitive/transitive] to realize or understand something
      None of us really knew what had gone wrong.
    2. b.
      [transitive] [often passive] used about things that most people think or believe are true
      The ancient city is known to have existed in the region.
      know someone/something to be something: The pilots were experienced and known to be very competent.
      know someone/something to do something: Some drugs are known to cause damage to unborn children.
  2. 2
    [transitive] to be familiar with someone, because you have met them or because you are friends
    Some of you may know Ivan already.
    I felt I hardly knew my father.
    She had known Nancy for years.
    1. b.
      to be familiar with things such as books, music, or art
      Do you know Beethoven’s Ninth Symphony?
    2. c.
      to be familiar with a process or system
      Do you know this program?
      You know the rules.
  3. 3
    [transitive] to use a particular name for someone or something
    know someone/something as something: The village was known as Garden Mill.
    know someone/something by something: They know all their tutors by their first names.
  4. 4
    [transitive] to remember or recognize someone because of a particular skill or quality that they have
    know someone as/for something: He was best known as a painter.
    We know her mostly for her love poetry.
  5. 5
    [transitive] to experience something
    It was the only comfort and warmth she had ever known.
    have never known someone (to) do something: I’ve never known her to make a joke.
  6. 6
    [transitive] to have learned a poem, story, or song, so that you can say it or sing it
    I still know the words to some of these hymns.
  7. 7
    [intransitive/transitive] to feel certain about something
    know (that): She knew it was Steven before she’d picked up the phone.
  8. 8
    [transitive] to recognize someone or something
    It was Henry: I would have known him anywhere.


phrasal verbs



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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