Definition of know verb from the Oxford Advanced American Dictionary

      

    know

     verb
    verb
    NAmE//noʊ//
     
    Verb Forms present simple I / you / we / they know
     
    he / she / it knows
     
    past simple knew
     
    past participle known
     
     
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  1. 1(not used in the progressive tenses)
  2. have information
  3. 2 [transitive, intransitive] to have information in your mind as a result of experience or because you have learned or been told it know something Do you know his address? The cause of the fire is not yet known. All I know is that she used to work in a bank (= I have no other information about her). know (that)… I know (that) people's handwriting changes as they get older. it is known that… It is widely known that CFCs can damage the ozone layer. know where, what, etc… I knew where he was hiding. I didn't know what he was talking about. know (of/about something) “You've got a flat tire.” “I know.” “What's the answer?” “I don't know.” “There's no one home.” “How do you know? You know about Amanda's baby, don't you? I don't know about you, butI'm ready for something to eat. I know of at least two people who did the same thing. “Is anyone else coming?” “Not that I know of. “Isn't that his car?” “I wouldn't know./How should I know?(= I don't know and I am not the person you should ask). (informal) “What are you two whispering about?” “You don't want to know.” (= because you would be shocked or wouldn't approve) know to do something Does he know to come here (= that he should come here) first? know somebody/something to be/do something We know her to be honest. Two women are known to have died. see also need-to-know
  4. realize
  5. 3[transitive, intransitive] to realize, understand, or be aware of something know (that)… As soon as I walked in the room I knew (that) something was wrong. She knew she was dying. know what, how, etc… I knew perfectly well what she meant. I know exactly how you feel. know (something) This case is hopeless and he knows it (= although he will not admit it). “Martin was lying the whole time.” “I should have known.”
  6. feel certain
  7. 4[transitive, intransitive] to feel certain about something know (that)… He knew (that) he could trust her. I know it's here somewhere! I know things will turn out all right. I don't know that I can finish it by next week. I just knew that it was something I wanted to do. know (something) “You were right—someone's been spreading rumors about you.” “I knew it!” “She's the worst player in the team.” “Oh,I don't know (= I am not sure that I agree) —she played well yesterday.”
  8. be familiar
  9. 5 [transitive] know somebody/something to be familiar with a person, place, thing, etc. I've known David for 20 years. Do you two know each other (= have you met before)? She was a secretary when I first knew her. She's very nice when you get to know her. Knowing Ben, we could be waiting a long time (= it is typical of him to be late). This man is known to the police (= as a criminal). I don't know anyone in Albuquerque. I know Savannah well. Do you know the play (= have you seen or read it before)? The new rules could mean the end of football as we know it (= in the form that we are familiar with).
  10. reputation
  11. 6[transitive, usually passive] to think that someone or something is a particular type of person or thing or has particular characteristics know somebody/something as something It's known as the most dangerous part of the city. know somebody/something for something She is best known for her work on the human brain. know somebody/something to be/do something He's known to be an outstanding physicist.
  12. give name
  13. 7 [transitive] know somebody/something as something [usually passive] to give someone or something a particular name or title Ascorbic acid is more commonly known as Vitamin C. Peter Wilson, also known as “the Tiger.”
  14. recognize
  15. 8[transitive] know somebody/something to be able to recognize someone or something I couldn't see who was speaking, but I knew the voice. She knows a bargain when she sees one. Thesaurusidentifyknow recognize name make somebody/something outThese words all mean to be able to see or hear someone or something and especially to be able to say who or what they are.identify to be able to say who or what someone or something is:He was able to identify his attacker.know to be able to say who or what something is when you see or hear it because you have seen or heard it before Know is used especially to talk about sounds that seem familiar and when someone recognizes the quality or opportunity that someone or something represents:I couldn't see who was speaking, but I knew the voice. She knows a bargain when she sees one.recognize to know who someone is or what something is when you see or hear them/it, because you have seen or heard them/it before:I recognized him as soon as he came into the room.name to say the name of someone or something in order to show that you know who/what they are:The victim has not yet been named in the newspapers.make somebody/something out to manage to see or hear someone or something that is not very clear:I could just make out a figure in the darkness.Patterns to identify/know/recognize somebody/something by something to identify/recognize/name somebody/something as somebody/something to identify/know/recognize/make out who/what/how… to easily/barely/just identify/recognize/make out somebody/something
  16. distinguish
  17. 9[transitive] know somebody/something from somebody/something to be able to distinguish one person or thing from another synonym differentiate I hope we have taught our children to know right from wrong.
  18. skill/language
  19. 10[transitive] to have learned a skill or language and be able to use it know something Do you know any Japanese? know how, what, etc… Do you know how to use spreadsheets?
  20. experience
  21. 11[transitive] (only used in the perfect tenses) to have seen, heard, or experienced something know somebody/something (to) do something I've never known it (to) snow in July before. be known to do something He has been known to spend all morning in the bathroom.
  22. 12[transitive] know something to have personal experience of something He has known both poverty and wealth. She may be successful now, but she has known what it is like to be poor.
  23. Idioms
    as far as I know,as far as I can remember, see, tell, etc.
     
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     used to say that you think you know, remember, understand, etc. something but you cannot be completely sure, especially because you do not know all the facts As far as we knew, there was no cause for concern. As far as I can see, you haven't done anything wrong. She lived in Chicago, as far as I can remember.
    before you know where you are
     
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    very quickly or suddenly We were whisked off in a taxi before we knew where we were.
    better the devil you know (than the devil you don't)(saying)
     
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    used to say that it is easier and wiser to stay in a bad situation that you know and can deal with rather than change to a new situation that may be much worse
    for all you, I, they, etc. know(informal)
     
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    used to emphasize that you do not know something and that it is not important to you She could be dead for all I know.
      God/goodness/Heaven knows(informal)
       
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    1. 1used to emphasize that you do not know something God knows what else they might find. “Where are they?” “Goodness knows.” Some people may find the use of God knows offensive.
    2. 2used to emphasize the truth of what you are saying She ought to pass the exam—goodness knows she's been working hard enough.
    have/know all the answers(informal)(often disapproving)
     
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    to be confident that you know something, especially when you actually do not He thinks he knows all the answers.
    have/know something down pat
     
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    to know something perfectly so that you can repeat it at any time without having to think about it He had all the answers down pat.
    have seen/known better days(humorous)
     
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    to be in poor condition Our car has seen better days!
    I don't know how, why, etc…(informal)
     
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    used to criticize someone's behavior I don't know how you can say things like that.
    if (the) truth be known/told
     
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    used to tell someone the true facts about a situation, especially when these are not known by other people
      I know(informal)
       
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    1. 1used to agree with someone or to show sympathy “What a ridiculous situation!” “I know.”
    2. 2 used to introduce a new idea or suggestion I know, let's see what's playing at the theater.
    know something as well as I do
     
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    used to criticize someone by saying that they should realize or understand something You know as well as I do that you're being unreasonable.
    know somebody/something backward and forward(informal)
     
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    to know someone or something extremely well She must know the play backward and forward by now.
    to know what should be done, etc. better than other people The doctor told you to stay in bed, and she knows best.
    know better (than that/than to do something)
     
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    to be sensible enough not to do something He knows better than to judge by appearances.
    know somebody by sight
     
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    to recognize someone without knowing them well
    know different/differently/otherwise(informal)
     
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    to have information or evidence that the opposite is true He says he doesn't care about what the critics write, but I know different.
    know full well
     
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    to be very aware of a fact and unable to deny or ignore it He knew full well what she thought of it.
    know somebody/something inside out,know somebody/something like the back of your hand(informal)
     
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    to be very familiar with something This is where I grew up. I know this area like the back of my hand.
    know your own mind
     
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    to have very firm ideas about what you want to do
    know your stuff(informal)
     
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    to know a lot about a particular subject or job
    know/tell somebody a thing or two (about somebody/something)(informal)
     
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    to know/tell someone some useful, interesting, or surprising information about someone or something She's been married five times, so she knows a thing or two about men!
    know your way around
     
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    to be familiar with a place, subject, etc.
    know what you're talking about(informal)
     
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    to have knowledge about something from your own experience I've lived in China, so I know what I'm talking about.
    know which side your bread is buttered (on)(informal)
     
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    to know where you can get an advantage for yourself
    let it be known/make it known that…(formal)
     
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    to make sure that people are informed about something, especially by getting someone else to tell them The President has let it be known that he does not intend to run for re-election.
    let somebody know
     
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    to tell someone about something I don't know if I can come, but I'll let you know tomorrow. Let me know how I can help.
    Lord knows…
     
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    used to emphasize what you are saying Lord knows, I tried to teach her.
    Lord (only) knows (what, where, why, etc.)…(informal)
     
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    used to say that you do not know the answer to something “Why did she say that?” “Lord knows!” Some people may find the use of Lord in these expressions offensive.
    make yourself known to somebody
     
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    to introduce yourself to someone I made myself known to the hotel manager.
    not know any better
     
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    to behave badly, usually because you have not been taught the correct way to behave Don't blame the children—they don't know any better.
    not know beans about something(informal)
     
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    to know nothing about a subject I don't know beans about making movies.
    not know the first thing about somebody/something
     
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    to know nothing at all about someone or something I'm afraid I don't know the first thing about cars.
    not know, etc. the first thing about something/somebody
     
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    to know nothing at all about something or someone We've lived next to him for years, but we still don't know the first thing about him.
    not know somebody from Adam(informal)
     
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    to not know at all who someone is
    not know what hit you(informal)
     
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    to be so surprised by something that you do not know how to react
    not know where to look(informal)
     
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    to feel great embarrassment and not know how to react
    not know whether you're coming or going(informal)
     
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    to be so excited or confused that you cannot behave or think in a sensible way
    old enough to know better
     
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    old enough to behave in a more sensible way than you actually did
    show somebody/know/learn the ropes(informal)
     
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    to show someone/know/learn how a particular job should be done
    there's no knowing
     
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    used to say that it is impossible to say what might happen There's no knowing how he'll react.
    what does… know?
     
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    used to say that someone knows nothing about the subject you are talking about What does he know about football, anyway?
    what do you know?(informal)
     
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    used to express surprise Well, what do you know? Look who's here!
      you know(informal)
       
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    1. 1used when you are thinking of what to say next Well, you know, it's difficult to explain.
    2. 2 used to show that what you are referring to is known or understood by the person you are speaking to Guess who I've just seen? Maggie! You know—Jim's wife. You know that restaurant around the corner? It's closing down.
    3. 3used to emphasize something that you are saying I'm not stupid, you know.
    you know something/what?(informal)
     
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    used to introduce an interesting or surprising opinion, piece of news, etc. You know something? I've never really enjoyed Christmas.
    you know who/what(informal)
     
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    used to refer to someone or something without mentioning a name
    you never know(informal)
     
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    used to say that you can never be certain about what will happen in the future, especially when you are suggesting that something good might happen
See the Oxford Advanced Learner's Dictionary entry: know