Meaning of ONE in English

ONE

I. one 1 S1 W1 /wʌn/ BrE AmE number

1 . the number 1:

They had one daughter.

one hundred and twenty-one pounds

Come back at one (=one o'clock) .

Katie’s almost one (=one year old) .

2 . one or two a small number of people or things SYN a few :

There are one or two things to sort out before I leave.

one or two of

One or two of us knew him quite well.

3 . in ones and twos British English alone or in pairs, rather than in large numbers or groups:

Guests arrived in ones and twos.

II. one 2 S1 W1 BrE AmE pronoun ( plural ones )

1 . used to mean someone or something of a type that has already been mentioned or is known about:

‘Have you got a camera?’ ‘No.’ ‘You should buy one (=buy a camera) .'

The train was crowded so we decided to catch a later one (=catch a later train) .

the one(s) (that/who/which)

The only jokes I tell are the ones that I hear from you.

this one/that one/these ones/those ones

I like all the pictures except this one.

2 . used to refer to a member of a group or pair of people or things:

The children seemed upset. One was crying.

She has two daughters. One is a primary school teacher, the other is a musician.

one of

One of the girls I work with is getting married.

This is one of my favourite books.

GRAMMAR

One of is followed by a plural noun but a singular verb:

One of the windows was open.

3 . the one(s) who/that the person or people who:

I was the one who had been attacked, not Richard.

The only ones who will benefit are the shareholders.

4 . one by one used when one person or thing in a group does something, then the next, then the next, especially in a regular way:

One by one each soldier approached the coffin and gave a final salute.

5 . one after another/one after the other if events happen one after the other, they happen without much time between them:

One after another, tropical storms battered the Pacific coastline.

6 . (all) in one if someone or something is many different things all in one, they are all those things:

It’s a TV, radio, and VCR all in one.

7 . formal used to mean people in general, including yourself:

One can never be too careful.

Great pictures make one think.

REGISTER

In everyday English, people usually use you rather than one :

You can never be too careful.

8 . I, for one, ... used to emphasize that you believe something, will do something etc and hope others will do the same:

I, for one, am proud of the team’s effort.

9 . ... for one used to give an example of someone or something:

There were several other people absent that afternoon, weren’t there? Mr Ashton for one.

10 . be one up (on somebody)/get one up on somebody to have or get an advantage over someone ⇨ ↑ one-upmanship

11 . put one over on somebody informal to trick someone:

No one’s going to put one over on me!

12 . be at one with somebody/something

a) to feel very calm or relaxed in the situation or environment you are in:

She felt as she always did in these mountains: peaceful, without care, at one with nature.

b) formal to agree with someone about something:

He was at one with Wheatley on the need to abandon free trade.

13 . informal used in particular phrases to mean ‘an alcoholic drink’:

How about a quick one at the pub?

have had one too many (=have drunk too much alcohol)

(have) one for the road (=have one last alcoholic drink before you leave a place)

14 . the one about ... spoken a joke or humorous story:

Have you heard the one about the chicken who tried to cross the road?

15 . as one written if many people do something as one, they all do it at the same time:

The whole team stood up as one.

16 . a difficult/hard/good etc one a particular kind of problem, question, story etc:

‘What do you attribute your long life to?’ ‘Oh that’s a difficult one’.

17 . one and the same the same person or thing:

Muhammad Ali and Cassius Clay are one and the same.

18 . not/never be one to do something informal to never do a particular thing, because it is not part of your character to do it:

Tom is not one to show his emotions.

19 . not/never be (a great) one for (doing) something informal to not enjoy a particular activity, subject etc:

I’ve never been a great one for watersports.

20 . one of us spoken used to say that someone belongs to the same group as you, or has the same ideas, beliefs etc:

You can talk in front of Terry – he’s one of us.

21 . one and all old-fashioned or formal everyone:

Apologies to one and all.

22 . got it in one! British English spoken used to say that someone has correctly guessed or understood something immediately:

‘You’re not painting the house again are you?’ ‘Got it in one!’

23 . little/young ones spoken used by some people to mean ‘children’, especially young children:

She’s got four little ones.

24 . you are/he is a one British English old-fashioned used to say that someone’s behaviour is amusing, strange, or surprising:

You are a one!

⇨ ↑ one-to-one

III. one 3 S1 W1 BrE AmE determiner

[ Language: Old English ; Origin: an ]

1 . used to emphasize a particular person or thing:

One person I find very difficult is Bob.

If there’s one thing I can’t stand, it’s people who bite their nails.

2 . one day/morning/year etc

a) on a particular day, morning etc in the past:

One morning I was sitting at my desk when a policeman knocked at my door.

b) used to talk about a day, morning etc in the future which is not yet exactly known or decided:

We should go out for a drink one evening.

One day she hopes to move to the South Coast.

3 . used to talk about a particular person or thing in comparison with other similar people or things:

Why does my card work in one cash machine and not in another?

4 . It’s one thing to ... it’s (quite) another to used to say that the second thing mentioned is very different from the first, and is often much more difficult to do:

It’s one thing to say we have a goal; it’s another to actually act on it.

5 . for one thing used to introduce a reason for what you have just said:

He couldn’t bring himself to say what he thought. For one thing, she seldom stopped to listen. For another, he doubted that he could make himself clear.

6 . be one crazy woman/be one interesting job etc especially American English spoken to be a very crazy woman, be a very interesting job etc:

You’re one lucky guy.

7 . formal used before the name of someone you do not know or have not heard of before SYN a certain :

He was accused of stealing a horse from one Peter Wright.

IV. one 4 BrE AmE adjective [only before noun]

1 . only:

Her one concern was to get to the door without being seen.

Claire is the one person I can trust.

2 . one and only

a) used to emphasize that someone is very famous:

the one and only Frank Sinatra

b) used to emphasize that something is the only one of its kind:

I even tried my one and only French joke on them.

V. one 5 BrE AmE noun [countable usually plural] American English

a piece of paper money worth one dollar:

I don’t have any ones.

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.