Definition of know in English:

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Pronunciation: /nəʊ/

verb (past knew /njuː/; past participle known /nəʊn/)

1 [with clause] Be aware of through observation, inquiry, or information: most people know that CFCs can damage the ozone layer I know what I’m doing
More example sentences
  • It's good to know that the authorities are aware of the need to protect our environment.
  • She said the bus companies knew that customers were very aware of green issues and clean fuel.
  • Anyone who has travelled to Holland knows that they are more aware of human rights.
be aware, realize, be conscious, have knowledge, be informed, have information;
notice, perceive, see, sense, recognize, understand, appreciate
informal savvy, latch on to something
1.1 [with object] Have knowledge or information concerning: I would write to him if I knew his address [no object]: I know of one local who shot himself
More example sentences
  • She is now growing increasingly concerned and wants anyone who may know of his whereabouts to get in contact.
  • Remember to let the kennels or cattery know of any particular feeding or other requirements for your pet.
  • Let it be clear from here on in that I know absolutely nothing about how cars work.
have knowledge of, be aware of, be cognizant of, be informed of, be apprised of
1.2Be absolutely certain or sure about something: I just knew it was something I wanted to do [with object]: I knew it!
More example sentences
  • It hurt thinking about it, knowing that there was absolutely nothing she could do.
  • We don't know that for sure till we do this clinical trial, but it is a possibility.
  • He would never let her go - no way; she knew that for sure - it was the only thing she was certain of.
2 [with object] Have developed a relationship with (someone) through meeting and spending time with them; be familiar or friendly with: he knew and respected Laura
More example sentences
  • Dave was well liked and respected by all who knew him.
  • He's quite shy but once you get to know him he's quite friendly.
  • She had only known him a few weeks, and she was already spending all of her time with him.
be acquainted with, have met, be familiar with;
be friends with, be friendly with, be on good terms with, be close to, be intimate with, socialize with, associate with, have dealings with;
understand, have insight into, be in sympathy with, empathize with;
Scottish  ken
informal be thick with
2.1Have a good command of (a subject or language).
Example sentences
  • One can listen to an aria in Italian or German without knowing the language and still get the message.
  • English children living in France would have to know the language - spoken and written.
  • This good news comes from someone who knows her subject.
be familiar with, be conversant with, be acquainted with, have knowledge of, be versed in, be knowledgeable about, have mastered, have a grasp of, grasp, understand, comprehend, apprehend;
have learned, have memorized, have learned by heart
informal be clued up on, have something taped
2.2Recognize (someone or something): Isabel couldn’t hear the words clearly but she knew the voice
More example sentences
  • Everyone knows the name and recognises the face but not many of us have actually gone to see him.
  • Yet Sven Goran Eriksson and his assistant clearly know a player when they see one.
  • One man recognises a room by a small sign, another knows a street by the tram car numbers.
2.3Be familiar or acquainted with (something): a little restaurant she knew near Leicester Square
More example sentences
  • Anybody familiar with Citroen's larger cars knows the comfort of its hydraulic suspension system.
  • The castles and heritage trails are known and savoured by visitors from near and far.
  • Andrea told me that all her girl friends know the site, which really flattered me.
2.4Have personal experience of (an emotion or situation): a man who had known better times
More example sentences
  • Today, he takes comfort in the fact that his eldest son knew personal happiness and fulfilment in the last few years of his life.
  • They knew plenty of personal pain and grief, but their country was inviolable and it prospered.
  • He is a man who has known much personal sorrow in his life, and yet that has not stopped him doing what he can for others.
experience, have experience of, go through, undergo, live through, meet, meet with, encounter, taste
2.5 (usually be known as) Regard or perceive as having a specified characteristic: the loch is known as a dangerous area for swimming
More example sentences
  • She kept those feelings locked away though; he was known as a lady-killer for a reason.
  • I hope as I go on in my career I will be known as a director who can tackle anything.
  • Do you want to be known as the girl that goes psycho if someone breaks up with her?
2.6 (usually be known as) Give (someone or something) a particular name or title: the doctor was universally known as ‘Hubert’
More example sentences
  • He does not use his title and is known by his first name at the university.
  • She was born in New York to Greek parents and, before she got her stage name, was known as Aikaterini Hadjipateras.
  • We certainly know that he did not use his first name Benjamin and was known as Olinde Rodrigues.
2.7 (know someone/thing from) Be able to distinguish one person or thing from (another): you are convinced you know your own baby from any other in the world
More example sentences
  • Certainly, he is a man who knows his arias from his oboes.
  • Anyway, we shall all know the answer in three weeks time but my vain hope would be that someone is put in charge of the agricultural portfolio who at least knows his sheep from his goats.
  • I solicited advice from a doctor friend who knows his asthma from his tennis elbow, and who has studied many branches of medicine.
distinguish, tell apart, differentiate, tell, tell which is which, discriminate;
recognize, pick out, identify, make out, discern, see
3 [with object] archaic Have sexual intercourse with (someone).
A Hebraism which has passed into modern languages; compare with German erkennen, French connaître
Example sentences
  • The angel tells Mary (a woman who has known no man) that she will bear a son.



and one knows it

Said to emphasize that someone is well aware of a fact although they might pretend otherwise: that’s nonsense and you know it
More example sentences
  • Oh my God, Rachael, that's not what I meant and you know it!
  • That's a lie and you know it!
  • They're breaking the goddamn law and they know it!

—— as we know it

As is familiar or customary in the present: apocalyptic expectations, envisaging the end of the world as we know it
More example sentences
  • We are witnessing the information revolution that will change the media as we know it.
  • Does the advent of downloading herald the demise of the album format as we know it - a tangible sequence of songs selected, ordered and packaged according to the intentions of the artist?
  • This level of remuneration did not result in the collapse of the book trade as we know it.

before one knows where one is (or before one knows it)

informal With baffling speed.
Example sentences
  • But when you're young, time seems endless and before you know it years have sped by.
  • If they split up, he'll be on your doorstep before you know it.
  • Get in debt with your mortgage and before you know it, your nightmares will have spiralled out of control.

be in the know

Be aware of something known only to a few people: he had a tip from a friend in the know: the horse was a cert
More example sentences
  • In today's information-based society, there are few things more infuriating than not being in the know.
  • Well, I used to pride myself as being in the know but I have heard nothing about this idea.
  • Essentially, one needs to be in the know to make the most of Berlin's nightlife.

be not to know

Have no way of being aware of: you weren’t to know he was about to die
More example sentences
  • In both cases the guns were not real, and not intended for criminal use, but the officers were not to know that.
  • She was not to know what leaving would do to my father.
  • Mr Newton was not to know that the builder on his doorstep had a string of convictions for deception and misleading customers.

don't I know it!

informal Used as an expression of rueful assent or agreement.
Example sentences
  • ‘You know how kids tease other kids with unusual names.’ ‘Oh, don't I know it! Try having to grow up with the name Jasper!’
  • ‘He's not the most forgiving person.’ Ryan laughed bitterly. ‘God, don't I know it.’

don't you know

informal, dated Used to emphasize what one has just said or is about to say: I was, don’t you know, a great motoring enthusiast in those days
More example sentences
  • Now Petey's a bishop himself, don't you know.
  • Used to be in the military myself, but it takes all kinds, don't you know?
  • Toronto-bashing is politically correct, don't you know, the Rest of Canada's national sport - second only to hockey - and the glue that keeps this country together.

for all someone knows

Used to express the limited scope or extent of one’s information: she could be dead for all I know
More example sentences
  • But for all Dirk knows, you could be out gallivanting.
  • In the refrigerator all she finds are some dried apples and celery and assorted condiments that could have been there since her last visit for all Sandra knows.
  • No-one asked her any questions, no-one searched her. She could have been a heroin mule or a gun smuggler for all anyone knew.

God (or goodness or heaven) knows

1Used to emphasize that one does not know something: God knows what else they might find
More example sentences
  • And heaven knows what the other tenants there must think.
  • And I really cannot be bothered to do any of the housework I've been putting off since, well, heaven knows when.
  • As for the houses which used to be on Clevelly Close, heaven knows how much they would be worth now, both in monetary terms and to the area's self-esteem.
2Used to emphasize the truth of a statement: goodness knows, I haven’t been perfect
More example sentences
  • Whatever you think of their relationship, and heaven knows it hasn't been an easy one, their love has endured.
  • ‘If it was like that for me, heaven knows, it must have been worse for others’, Mr Cook said.
  • It is easy to be derisory about politics in Ireland, and, heaven knows, there is much to be derisory about.

have been known to do something

Have occasionally in the past done something: the fans have been known to rain bottles, cans, and seats on players who displease them
More example sentences
  • What I managed to avoid doing was panic and start talking really fast as I have been known to do in the past.
  • Even the best of our past leaders have been known to falter on this very question.
  • Don't get me wrong I love a good drink and am a social smoker and in the past have been known to smoke cannabis.

I know

1I agree: ‘It’s not the same without Rosie.’ ‘I know.’
More example sentences
  • ‘She'll be really annoyed if you sneak off to go drinking with us at some bar. Especially without her.’ ‘I know.’
2 (also I know what) I have a new idea or suggestion: I know what, let’s do it now
More example sentences
  • I know what, why don't we grab a little bite downstairs and then I'll take you by the house so you can meet the guys.
  • I know what! I'll fix strawberries just the way you like them! What do you say to that?

know something backwards


know best

Have better knowledge or more appropriate skills: a mother always knows best where her children are concerned
More example sentences
  • The left have always believed that governments know best.
  • Thankfully, mums always know best and by the age of 13 Susie was gradually able to start playing sport again.
  • I was put on Prozac and the doc suggested counseling, which I never took - in retrospect maybe I should have but I thought I knew best, as always.

know better than

Be wise or polite enough to avoid doing a particular thing: you ought to know better than to ask that
More example sentences
  • The 55-year-old veteran of the international scene knows better than to expect instant success.
  • He knows better than to ask me if I've had a nice day when I get home from work or whether the children have been good while he's been out.
  • Experienced political campaigners know better than to argue with a tough minded person like yourself.

know someone by sight

Recognize someone by their appearance without knowing their name or being so well acquainted as to talk to them.
Example sentences
  • The woman and her family moved here from France sometime earlier this year, I didn't know her name but I knew her by sight.
  • We all knew them by sight and they seemed a truly lovely family.
  • I had known his brother very well at junior school and I knew Freddie by sight.

know different (or otherwise)

Be aware of information or evidence to the contrary.
Example sentences
  • If you didn't know otherwise, it would be perfectly reasonable to assume the school in question would be open to all, especially thanks to the use of the friendly words ‘junior school’.
  • Until I know otherwise I'll be starting pre-season training at Fulham.
  • We may smile now at our erstwhile belief that the sun circles the earth rather than the other way round, or that the earth is flat, but the only reason we know different is that a scientific genius dispelled our illusions.

know something for a fact

Be aware of something that is irrefutable or beyond doubt: I know for a fact that he can’t speak a word of Japanese
More example sentences
  • If you know the answer for a fact, please get in touch.
  • I've heard it said many times, and been long enough on this earth to know it for a fact, that marriage, as a rule, changes women more than men.
  • I know for a fact that his mother and father didn't have any siblings, so he doesn't have any cousins.

know someone in the biblical sense

informal, humorous Have sexual intercourse with someone.
Example sentences
  • I didn't know him from Adam, though it might have been nice to know him in the biblical sense, ha ha.
  • Well I never knew her in the biblical sense, we just bumped into each other at some party and you know how it goes.
  • ‘I take it you know her?’ Holly asked. ‘Yes,’ Pete said, ‘And, because I know you're curious, yes, I knew her in the biblical sense as well.’

know no bounds

Have no limits: their courage knows no bounds
More example sentences
  • Similarly, man's imagination has no limits and his inventiveness knows no bounds.
  • One could say their generosity knows no bounds.
  • Clearly, the ego of this deluded man knows no bounds.

know one's own mind

Be decisive and certain.
Example sentences
  • It's been an eye-opener for the whole family, but she's 20 years old, she knows her own mind and she can make her own decisions.
  • In Russia he also has a reputation as a coach who knows his own mind and is not afraid to speak it, something which has not always pleased his club presidents.
  • We like Ken, he knows his own mind and never panders to the media or the public.

know one's way around (or about)

Be familiar with (an area, procedure, or subject).
Example sentences
  • Cottrell has been a coach since 1981, so he knows his way around the league.
  • Presumably Davies knows his way around the Hollywood A-list well enough.
  • Although he is a relative newcomer to the lobbying game, Livingston obviously knows his way around the halls of Congress and how to pitch for a client.

know the ropes

Have experience of the appropriate procedures.
With reference to ropes used in sailing
Example sentences
  • He has been in the limelight for six years now and knows the ropes.
  • He had minimal playing experience in the majors, but he has been in baseball since the '70s and knows the ropes.
  • One of the most efficient and safest ways to see the most sights in the least amount of time is with a tour guide who knows the ropes.

know what one likes

Have fixed or definite tastes, without necessarily having the knowledge or informed opinion to support them: I don’t understand all this modern poetry at all, but I know what I like
More example sentences
  • I don't feel qualified to comment as a music critic, but I know what I like, and I enjoyed many of the musical selections.
  • I don't know a damn thing about photography, but I know what I like.

know what's what

informal Be experienced and competent in a particular area.
Example sentences
  • Peritz, in truth, is an inherently humble guy who knows what's what.
  • Yes, you guessed it - the subject is the upcoming election, and the political scientists think they know what's what.
  • Hire a crew of people who have put on such shows before, and who know what's what.

know who's who

Be aware of the identity and status of each person.
Example sentences
  • Ensure that they know who's who and can identify company structure, individual roles and the existing communicative systems in use as soon as possible.
  • We're on a first-name basis with a lot of people and we know who's who in the community.
  • This invaluable data base will be expanded and updated, helping us - and the media - know who's who in the corporate-scientific complex.

let it be (or make something) known

Ensure that people are informed about something, especially via a third party: [with clause]: the Minister let it be known that he was not seeking reappointment
More example sentences
  • Once the manufacturer gets the results, it can choose whether to make the information known to the public.
  • Ireland has operated a voluntary reporting system since 1985, but there is no statutory requirement on doctors to make cases known to public health authorities.
  • Anyone with information about any violent attacks or murders should make it known to the Police immediately.

not know from nothing

North American informal Be totally ignorant: she shakes her head while you talk, as if to say you don’t know from nothing
More example sentences
  • You don't know from nothing about girls, do you?
  • He knew from nothing about playing a piano, but his daughter did and from what she'd told him Steinway was one of the premier piano makers in the world.

not know the first thing about

Have not the slightest idea about (something): he’s an engineer, doesn’t know the first thing about literature
More example sentences
  • I don't know the first thing about firearms; I have never even held a gun.
  • Most kids his age don't know the first thing about politics.
  • That was easy for me - I don't know the first thing about football.

not know that

informal Used to express one’s doubts about one’s ability to do something: I don’t know that I can sum up my meaning on paper
More example sentences
  • I don't know that there's anything you can do; I think you've got to leave it up to him.
  • I don't know that I can be any more specific than that because there are court proceedings pending.
  • I don't know that I could go back to having a full-time job.

not know what hit one

Be very shocked or surprised by a sudden attack or event.
Example sentences
  • Friday night at Sam's Town Casino, five miles south of the Las Vegas strip: The unsuspecting locals didn't know what hit them.
  • Michigan Democrat Carl Levin still doesn't know what hit him.
  • Quite often what happens is that young men are relatively unaware of their emotions until something goes wrong and then very often they don't know what hit them.

not know what to do with oneself

Be at a loss as to know what to do, typically through boredom, embarrassment, or anxiety.
Example sentences
  • We do meet older people whose children have gone to university and they don't know what to do with themselves.
  • We are absolutely devastated, we just don't know what to do with ourselves.
  • It had become such a habit that I almost don't know what to do with myself now…

not know where (or which way) to look

Feel great embarrassment and not know how to react.
Example sentences
  • The nave cracked up, the priest didn't know where to look, and Granny was mortified.
  • ‘Are you pregnant?’ Ruthy didn't know where to look. ‘You're pregnant, right?’
  • It was embarrassing for us. We didn't know where to look. All the family were getting really frustrated that she hadn't shown up.

not want to know

informal Refuse to react or take notice: they just didn’t want to know when I gave my side of the story
More example sentences
  • Unless you're awfully special, the market doesn't want to know.
  • Because we are off the beaten track, the council doesn't want to know.
  • I am responsible for him but I am told nothing can be done without his agreement, and he doesn't want to know.

what does —— know?

informal Used to indicate that someone knows nothing about the subject in question: what does he know about football, anyway?
More example sentences
  • He lives with his wife and daughter in a $1.9 million home in Manhattan, what does he know about the minimum wage?
  • The video seems odd to me, but it's probably the first rock video I've seen in about eight years, so what do I know?

what do you know (about that) ?

North American informal Used as an expression of surprise.
Example sentences
  • Well what do you know, she does listen to me once in a while.
  • Well, what do you know; he is good for something besides eating and sleeping!
  • And what do you know, this evening my uncle turned up.

wouldn't you like to know?

informal Used to express one’s intention to keep something secret despite another’s curiosity: ‘You’re loaded, aren’t you, Bella?’ ‘Wouldn’t you like to know?’
More example sentences
  • ‘How did he get out?’ Aubrey smirked. ‘Wouldn't you like to know?’
  • ‘Where are you going?’ asked Pete. ‘Wouldn't you like to know?’ she said, heading for the door.

you know

Used to indicate that what is being referred to is known to or understood by the listener: when in Rome, you know
37.1Used as a filler in conversation: oh well, you know, I was wondering if you had any jobs for me
More example sentences
  • I fear it may take me some time to get back into, you know, writing, so bear with me.
  • There has to be a lot of open floor, a lot of room for people to jump up and dance, you know?
  • So it's been like a new music adventure for me now, you know, like starting all over again.

you know something (or what) ?

informal Used to indicate that one is going to say something interesting or surprising: You know what? I believed her
More example sentences
  • They pulled me, poked me, sucked blood out of me, pumped drugs into me, and you know what? They still couldn't find anything wrong with me.
  • But you know something, my job is to uphold the laws of the state.
  • Well, you know something, the strangest thing is that I never went to counseling for 20 years after Adam.

you never know

informal You can never be certain.
Example sentences
  • And you never know, you might even find your game improves.
  • Maybe someone will smuggle me a contraband glass of wine, you never know.
  • Of course, you never know, there might be an ambitious young politician who wants to run this campaign.



Pronunciation: /ˈnəʊəb(ə)l/
Example sentences
  • It would be wonderful if everything were knowable a year and a half in advance, but it isn't.
  • If these measurements are a way of attempting to gain control of an unpredictable world by making it rational and knowable, how do we react when all of our familiar scales are unbalanced?
  • Young children think that the world is defined and that everything in their experience and that of the people closest to them is knowable.


Pronunciation: /ˈnəʊə/
Example sentences
  • A reciprocal relationship between the knower and the known, common to all the sciences, is important here.
  • Solution-focused therapy honors families as knowers of their experience with sufficient resources to define treatment goals and achieve change.
  • Family members described their role as helpers and knowers of the patient.


Old English cnāwan (earlier gecnāwan) 'recognize, identify', of Germanic origin; from an Indo-European root shared by Latin (g)noscere, Greek gignōskein, also by can1 and ken.

  • The ancient root of know is shared by can and ken, ‘to know’ in Scots (all Old English), and also by Latin noscere, and Greek gignōskein ‘to know’, source of words such as agnostic. To know in the biblical sense, meaning ‘to have sex with’, comes from biblical uses such as the verse in the book of Genesis: ‘And Adam knew Eve his wife; and she conceived, and bare Cain.’ To know the ropes is to be thoroughly acquainted with the way in which something is done. The phrase comes from the days of sailing ships, when skill in handling ropes was essential for any sailor—an alternative is know their onions. The ancients valued self-knowledge as the way to wisdom—inscribed on the Greek temple of Apollo at Delphi were the words know thyself. The line ‘ It's life, Jim, but not as we know it’ is the mainstay of anyone trying to do an impression of Dr Spock from the TV series Star Trek, but he never said it in the programme. He did say that there was ‘no life as we know it’, but the quoted phrase is from the 1987 song ‘Star Trekkin'’ by the Firm. See also gnome

Words that rhyme with know

aglow, ago, alow, although, apropos, art nouveau, Bamako, Bardot, beau, Beaujolais Nouveau, below, bestow, blow, bo, Boileau, bons mots, Bordeaux, Bow, bravo, bro, cachepot, cheerio, Coe, crow, Defoe, de trop, doe, doh, dos-à-dos, do-si-do, dough, dzo, Flo, floe, flow, foe, foreknow, foreshow, forgo, Foucault, froe, glow, go, good-oh, go-slow, grow, gung-ho, Heathrow, heave-ho, heigh-ho, hello, ho, hoe, ho-ho, jo, Joe, kayo, lo, low, maillot, malapropos, Marceau, mho, Miró, mo, Mohs, Monroe, mot, mow, Munro, no, Noh, no-show, oh, oho, outgo, outgrow, owe, Perrault, pho, po, Poe, pro, quid pro quo, reshow, righto, roe, Rouault, row, Rowe, sew, shew, show, sloe, slow, snow, so, soh, sow, status quo, stow, Stowe, strow, tally-ho, though, throw, tic-tac-toe, to-and-fro, toe, touch-and-go, tow, trow, undergo, undersow, voe, whacko, whoa, wo, woe, Xuzhou, yo, yo-ho-ho, Zhengzhou, Zhou

For editors and proofreaders

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