Definition of know

knowverb
hiểu biết, nhận biết
/nəʊ/

The word "know" has its roots in Old English and is derived from the Proto-Germanic word "*kunniz," which meant "to know how" or "to be able to." This Proto-Germanic word is thought to have been formed from two parts: "*kunthiz," meaning "to seem" or "to appear," and "*(-h)iz," which is a verb-forming suffix. The Old English word "cunnan" or "cunnon" meant "to know how to do something" or "to be able to," and it was often used in combination with other words to form phrases such as "Ic cunne wel" (I know well) or "Hwæt ic cunne" (What I know). Over time, the meaning of the word "know" expanded to include not just knowledge of how to do something, but also knowledge about something, or recognition of something. Today, the word "know" is a common and versatile term that is used in many different contexts.

Summary

động từ knew; known
meaning

biết; hiểu biết
example

to know about something: biết về cái gì
example

to know at least three languages: biết ít nhất ba thứ tiếng
example

to know how to play chess: biết đánh cờ
meaning

biết, nhận biết; phân biệt được
example

to know somebody at once: nhận biết được ai ngay lập tức
example

to know one from another: phân biệt được cái này với cái khác
meaning

biết, quen biết
example

to know by sight: biết mặt
example

to know by name: biết tên
example

to get to know somebody: làm quen được với ai
type

danh từ (thông tục)
meaning

to be in the know biết rõ sự việc, biết rõ vấn đề; biết điều mà mọi người chưa biết
example

to know about something: biết về cái gì
example

to know at least three languages: biết ít nhất ba thứ tiếng
example

to know how to play chess: biết đánh cờ

have information

to have information in your mind as a result of experience or because you have learned or been told it

có thông tin trong đầu bạn nhờ kinh nghiệm hoặc vì bạn đã học được hoặc được cho biết về nó

Example:

No one knows the answer.
Không ai biết câu trả lời.
I need to know your name.
Tôi cần biết tên của bạn.
The truth about what happened is not yet known.
Sự thật về những gì đã xảy ra vẫn chưa được biết.
All I know is that she used to work in a bank (= I have no other information about her).
Tất cả những gì tôi biết là cô ấy từng làm việc ở ngân hàng (= tôi không có thông tin nào khác về cô ấy).
I know (that) people’s handwriting changes as they get older.
Tôi biết (rằng) chữ viết tay của mọi người thay đổi khi họ già đi.
We know from experience that turning a hobby into a business is not easy.
Qua kinh nghiệm, chúng tôi biết rằng việc biến sở thích thành công việc kinh doanh không hề dễ dàng.
I know for a fact (that) he didn't go to the party.
Tôi biết sự thật là anh ấy đã không đến bữa tiệc.
‘There's no one in.’ ‘How do you know?’
“Không có ai ở trong cả.” “Sao cậu biết?”
‘You've got a flat tyre.’ ‘I know.’
‘Anh bị xẹp lốp.’ ‘Tôi biết.’
‘What's the answer?’ ‘I don't know.’
‘Câu trả lời là gì?’ ‘Tôi không biết.’
As you know, Emma and I are old friends.
Như bạn đã biết, Emma và tôi là bạn cũ.
‘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.)
‘Đó không phải là xe của anh ấy sao?’ ‘Tôi không biết./Làm sao tôi biết được?’ (= Tôi không biết và tôi không phải là người bạn nên hỏi.)
‘What are you two whispering about?’ ‘You don't want to know’ (= because you would be shocked or wouldn't approve).
‘Hai bạn đang thì thầm về điều gì?’ ‘Bạn không muốn biết’ (= bởi vì bạn sẽ bị sốc hoặc sẽ không chấp nhận).
It is widely known that CFCs can damage the ozone layer.
Người ta biết rộng rãi rằng CFC có thể làm hỏng tầng ozone.
I knew where he was hiding.
Tôi biết anh ta đang trốn ở đâu.
No one knows for sure who did it.
Không ai biết chắc chắn ai đã làm điều đó.
You know about Amanda's baby, don't you?
Bạn biết về con của Amanda phải không?
I don't know about you, but I'm ready for something to eat.
Không biết bạn thế nào, nhưng tôi đã sẵn sàng ăn gì đó.
I know next to nothing (= know almost nothing) about opera.
Tôi gần như không biết gì (= hầu như không biết gì) về opera.
I know of someone who can help us.
Tôi biết một người có thể giúp chúng tôi.
‘Is anyone else coming?’ ‘Not that I know of.’
“Có ai khác đến không?” “Tôi không biết.”
Does he know to come here (= that he should come here) first?
Anh ấy có biết đến đây (= rằng anh ấy nên đến đây) trước không?
We know her to be honest.
Chúng tôi biết cô ấy thành thật.
Strobe lights are known to cause seizures.
Đèn nhấp nháy được biết là có thể gây co giật.

Extra examples:

Do you know his address?
Bạn có biết địa chỉ của anh ấy không?
The cause of the fire is not yet known.
Hiện chưa rõ nguyên nhân vụ cháy.
Two women are known to have died.
Hai người phụ nữ được biết là đã chết.
I didn't know what he was talking about.
Tôi không biết anh ấy đang nói về điều gì.
I need to know what everyone thinks about this.
Tôi cần biết mọi người nghĩ gì về điều này.

Related words and phrases

realize

to realize, understand or be aware of something

để nhận ra, hiểu hoặc nhận thức được một cái gì đó

Example:

As soon as I walked in the room I knew (that) something was wrong.
Ngay khi bước vào phòng tôi đã biết có điều gì đó không ổn.
She knew she was dying.
Cô biết mình sắp chết.
‘Martin was lying all the time.’ ‘I should have known.’
“Martin đã nói dối mọi lúc.” “Lẽ ra tôi phải biết.”
I knew perfectly well what she meant.
Tôi biết rất rõ ý cô ấy là gì.
I know exactly how you feel.
Tôi biết chính xác bạn cảm thấy thế nào.
This case is hopeless and he knows it (= although he will not admit it).
Trường hợp này là vô vọng và anh ấy biết điều đó (= mặc dù anh ấy sẽ không thừa nhận điều đó).

Extra examples:

If only we'd known you were having so many problems!
Giá như chúng tôi biết bạn đang gặp rất nhiều vấn đề!
You know very well what I'm talking about!
Bạn biết rất rõ tôi đang nói về điều gì!
If I'd known beforehand how bad it would be, I wouldn't have gone.
Nếu biết trước sẽ tệ đến thế nào thì tôi đã không đi.
I instantly knew what the call was about.
Tôi ngay lập tức biết cuộc gọi nói về điều gì.
He knew instinctively where he would find her.
Theo trực giác, anh biết mình sẽ tìm thấy cô ở đâu.

feel certain

to feel certain about something

cảm thấy chắc chắn về điều gì đó

Example:

He knew (that) he could trust her.
Anh ấy biết (rằng) anh ấy có thể tin tưởng cô ấy.
I know it's here somewhere!
Tôi biết nó ở đâu đó ở đây!
I know things will turn out all right.
Tôi biết mọi chuyện sẽ ổn thôi.
I don't know that I can finish it by next week.
Tôi không biết liệu tôi có thể hoàn thành nó vào tuần tới không.
I just knew that it was something I wanted to do.
Tôi chỉ biết rằng đó là điều tôi muốn làm.
‘You were right—someone's been spreading rumours about you.’ ‘I knew it!’
‘Bạn đã đúng – ai đó đã lan truyền tin đồn về bạn.’ ‘Tôi biết điều đó!’
‘She's the worst player in the team.’ ‘Oh, I don't know (= I am not sure that I agree)—she played well yesterday.’
‘Cô ấy là người chơi tệ nhất trong đội.’ ‘Ồ, tôi không biết (= tôi không chắc là mình đồng ý)—hôm qua cô ấy đã chơi tốt.’

Extra examples:

She knew deep down that she would never see him again.
Trong thâm tâm cô biết rằng cô sẽ không bao giờ gặp lại anh nữa.
He knew that he could trust her.
Anh biết rằng anh có thể tin tưởng cô.
I just knew there would be problems.
Tôi chỉ biết sẽ có vấn đề.

Related words and phrases

be familiar

to be familiar with a person, place, thing, etc.

làm quen với một người, địa điểm, đồ vật, v.v.

Example:

I've known David for 20 years.
Tôi đã biết David được 20 năm.
Do you two know each other (= have you met before)?
Hai bạn có biết nhau không (= bạn đã gặp nhau trước đây chưa)?
She was a secretary when I first knew her.
Cô ấy là thư ký khi tôi mới biết cô ấy.
She's very nice when you get to know her.
Cô ấy rất tốt khi bạn làm quen với cô ấy.
Knowing Ben, we could be waiting a long time (= it is typical of him to be late).
Biết Ben, chúng tôi có thể chờ đợi rất lâu (= điển hình là anh ấy đến muộn).
This man is known to the police (= as a criminal).
Người đàn ông này được cảnh sát biết đến (= là tội phạm).
I don’t know anyone in Oxford.
Tôi không biết ai ở Oxford cả.
I know Paris well.
Tôi biết rõ về Paris.
Do you know the play (= have you seen or read it before)?
Bạn có biết vở kịch (= bạn đã xem hoặc đọc nó trước đây chưa)?
How many of your neighbours do you know by name?
Bạn biết tên bao nhiêu người hàng xóm?
The new rules could mean the end of football as we know it (= in the form that we are familiar with).
Các quy tắc mới có thể có nghĩa là sự kết thúc của bóng đá như chúng ta biết (= ở dạng mà chúng ta quen thuộc).

Extra examples:

He knows this city better than anyone.
Anh ấy hiểu rõ thành phố này hơn bất kỳ ai.
I don't know them personally.
Cá nhân tôi không biết họ.
I don't know John very well.
Tôi không biết rõ về John.
But I hardly know the woman!
Nhưng tôi hầu như không biết người phụ nữ đó!
I know several people who could help.
Tôi biết một số người có thể giúp đỡ.

skill/language

to have learned a skill or language and be able to use it

đã học được một kỹ năng hoặc ngôn ngữ và có thể sử dụng nó

Example:

Do you know any Japanese?
Bạn có biết tiếng Nhật nào không?
Do you know how to use spreadsheets?
Bạn có biết cách sử dụng bảng tính không?

reputation

to think that somebody/something is a particular type of person or thing or has particular characteristics

nghĩ rằng ai đó/cái gì đó là một loại người hoặc vật cụ thể hoặc có những đặc điểm cụ thể

Example:

He has become widely known as an expert in child psychology.
Ông đã được biết đến rộng rãi như một chuyên gia về tâm lý trẻ em.
It's known as the most dangerous part of the city.
Nó được biết đến là khu vực nguy hiểm nhất của thành phố.
She is best known for her work on the human brain.
Cô được biết đến nhiều nhất với công việc nghiên cứu về bộ não con người.
He is internationally known for his work with vaccines.
Ông được cả thế giới biết đến nhờ công việc nghiên cứu vắc xin.
He's known to be an outstanding physicist.
Ông được biết đến là một nhà vật lý xuất sắc.

Related words and phrases

well known (1)

give name

to give somebody/something a particular name or title

đặt cho ai/cái gì một cái tên hoặc chức danh cụ thể

Example:

Iran was formerly known as Persia.
Iran trước đây được gọi là Ba Tư.
The drug is commonly known as Ecstasy.
Loại thuốc này thường được gọi là thuốc lắc.
Peter Wilson, also known as ‘The Tiger’
Peter Wilson, còn được gọi là 'Con hổ'
He was known as Bonzo to his friends.
Anh ấy được bạn bè gọi là Bonzo.
The country was not yet known by the name of England.
Đất nước này vẫn chưa được biết đến với cái tên Anh.

Extra examples:

parts of the body known collectively as the sensory system
các bộ phận của cơ thể được gọi chung là hệ thống cảm giác
The drug is variously known as crack or freebase.
Thuốc có nhiều tên gọi khác nhau là crack hoặc freebase.
He has been known by many names in his long life.
Ông đã được biết đến với nhiều cái tên trong suốt cuộc đời lâu dài của mình.

recognize

to be able to recognize somebody/something

có thể nhận ra ai/cái gì đó

Example:

I couldn't see who was speaking, but I knew the voice.
Tôi không thể nhìn thấy ai đang nói, nhưng tôi biết giọng nói đó.
She knows a bargain when she sees one.
Cô ấy biết một món hời khi cô ấy nhìn thấy một món hời.

understand the difference

to understand the difference between one person or thing and another

để hiểu sự khác biệt giữa một người hoặc vật và người khác

Example:

I hope we have taught our children to know right from wrong.
Tôi hy vọng chúng ta đã dạy con mình biết đúng sai.

Related words and phrases

experience

to have seen, heard or experienced something

đã thấy, nghe hoặc trải nghiệm điều gì đó

Example:

I’ve never known it (to) snow in July before.
Tôi chưa bao giờ biết tuyết rơi vào tháng 7 trước đây.
He has been known to spend all morning in the bathroom.
Người ta biết rằng anh ta dành cả buổi sáng trong phòng tắm.

to have personal experience of something

có kinh nghiệm cá nhân về điều gì đó

Example:

He has known both poverty and wealth.
Anh ta đã biết đến cả nghèo khó và giàu có.
She may be successful now, but she has known what it is like to be poor.
Bây giờ cô ấy có thể thành công nhưng cô ấy đã biết cảm giác nghèo khó là như thế nào.
She thought she would never know the joy of seeing a child grow up in her care.
Cô nghĩ mình sẽ không bao giờ biết được niềm vui khi nhìn thấy một đứa trẻ lớn lên trong sự chăm sóc của mình.

Related words and phrases

Idioms

as far as I know | as far as I can remember, see, tell, etc.

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've done nothing wrong.

She lived in Chicago, as far as I can remember.

before you know where you are

very quickly or suddenly

We were whisked off in a taxi before we knew where we were.

be not to know

to have no way of realizing or being aware that you have done something wrong

‘I'm sorry, I called when you were in bed.’ ‘Don't worry—you weren't to know.’

better the devil you know (than the devil you don’t)

(saying)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)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

used to emphasize that you do not know something

God knows what else they might find.

‘Where are they?’ ‘Goodness knows.’

used 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)to be confident that you know something, especially when you actually do not

He thinks he knows all the answers.

have/know something off pat

to know something perfectly so that you can repeat it at any time without having to think about it

He had all the answers off pat.

have seen/known better days

(humorous)to be in poor condition

Our car has seen better days!

I don’t know how, why, etc…

(informal)used to criticize somebody’s behaviour

I don't know how you can say things like that.

if (the) truth be known/told

used to tell somebody the true facts about a situation, especially when these are not known by other people

If the truth be known, I was afraid to tell anyone.

I know

used to agree with somebody or to show sympathy

‘What a ridiculous situation!’ ‘I know.’

used to introduce a new idea or suggestion

I know, let's see what's on at the theatre.

know something as well as I do

used to criticize somebody by saying that they should realize or understand something

You know as well as I do that you're being unreasonable.

know somebody/something backwards

(especially British English, informal)to know somebody/something extremely well

She must know the play backwards by now.

know best

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)

to be sensible enough not to do something

He knows better than to judge by appearances.

know somebody by sight

to recognize somebody without knowing them well

know different/otherwise

(informal)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

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)to be very familiar with somebody/something

This is where I grew up. I know this area like the back of my hand.

know your own mind

to have very clear and definite ideas about what you want to do

know your stuff

(informal)to know a lot about a particular subject or job

know/tell somebody a thing or two (about somebody/something)

(informal)to know/tell somebody some useful, interesting or surprising information about somebody/something

She's been married five times, so she knows a thing or two about men!

know/learn/find something to your cost

to know something because of something unpleasant that has happened to you

She is a tough competitor, as I know to my cost.

know your way around

to be familiar with a place, subject, etc.

know what you’re talking about

(informal)to have knowledge about something from your own experience

I worked there for 20 years, so I know what I'm talking about.

know which side your bread is buttered

(informal)to know where you can get an advantage for yourself

let it be known/make it known that…

(formal)to make sure that people are informed about something, especially by getting somebody else to tell them

The President has let it be known that he does not intend to run for election again.

let somebody know

to tell somebody about something

I don't know if I can come, but I'll let you know tomorrow.

Let me know how I can help.

Please let me know if there's anything I can do to help.

Lord knows…

used to emphasize what you are saying

Lord knows, I tried to teach her.

Lord (only) knows (what, where, why, etc.)…

(informal)used to say that you do not know the answer to something

‘Why did she say that?’ ‘Lord knows!’

make yourself known to somebody

to introduce yourself to somebody

I made myself known to the hotel manager.

not know any better

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 your arse from your elbow

(British English, offensive, slang)to be very stupid; to have absolutely no skill

not know beans about something

(North American English, informal)to know nothing about a subject

I don’t know beans about making movies.

not know the first thing about somebody/something

to know nothing at all about somebody/something

I’m afraid I don’t know the first thing about cars.

not know, etc. the first thing about something/somebody

to know nothing at all about something/somebody

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)to not know at all who somebody is

not know what hit you

(informal)to be so surprised by something that you do not know how to react

not know where to look

(informal)to feel very embarrassed and not know how to react

not know whether you’re coming or going

(informal)to be so excited or confused that you cannot behave or think in a sensible way

not know you are born

(British English, informal)to have an easy life without realizing how easy it is

You people without kids don't know you're born.

not want to know (about something)

(informal)to take no interest in something because you do not care about it or it is too much trouble

I've tried to ask her advice, but she doesn't want to know (= about my problems).

‘How much was it?’ ‘You don't want to know’ (= it is better if you don't know).

old enough to know better

old enough to behave in a more sensible way than you actually did

show somebody/know/learn the ropes

(informal)to show somebody/know/learn how a particular job should be done

there’s no knowing

used to say that it is impossible to say what might happen

There's no knowing how he'll react.

what does… know?

used to say that somebody knows nothing about the subject you are talking about

What does he know about football, anyway?

what do you know?

(informal)used to express surprise

Well, what do you know? Look who's here!

(know) what’s what

(informal)(know) what things are useful, important, etc.

She certainly knows what's what.

you know

used when you are thinking of what to say next

Well, you know, it's difficult to explain.

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 round the corner? It's closed down.

used to emphasize something that you are saying

I'm not stupid, you know.

you know something/what?

(informal)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)used to refer to somebody/something without mentioning a name

you never know

(informal)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

Definition of know

knowverbhiểu biết, nhận biết/nəʊ/

Related words and phrases

Idioms

knowverb
hiểu biết, nhận biết
/nəʊ/