Meaning of “one” in the English Dictionary

"one" in British English

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onenumber, determiner

uk /wʌn/ us /wʌn/

one number, determiner (NUMBER)

A1 the number 1:

He had two slices and I only had one.
She'll be one year old tomorrow.

More examples

  • Trouble broke out in the match when one of the players called a member of the other team a cheat.
  • They've got two adopted children and one of their own.
  • He is one of the top chefs in Britain.
  • When one engine stopped, we had to turn round and fly home.
  • Would you run your idea by me one more time?
  • Four parcels came this morning, but only one was for Mark.
  • Paint one side, leave it to dry, and then paint the other.
  • He can't tell one wine from another, so don't give him any of the expensive stuff.

one number, determiner (MEMBER)

one of

A2 a member of a group of people or things:

One of their daughters has just had a baby.
EMI is one of the world's largest record companies.
Finding a cure for cancer is one of the biggest challenges facing medical researchers.
Our organization is just one of many charities that are providing famine relief in the region.

one number, determiner (FUTURE TIME)

B2 used to refer to a time in the future that is not yet decided:

Why don't we meet for lunch one day next week?
I'd like to go skiing one Christmas.

More examples

  • You're going to get into serious trouble one of these days.
  • Let's go to the cinema one night next week.
  • One of these days we're going to move to France.
  • Come and visit one weekend.
  • One day we'll be able to afford a car like that.

one number, determiner (PARTICULAR OCCASION)

B2 used to refer to a particular occasion while avoiding stating the exact moment:

One night we stayed up talking till dawn.
He was attacked as he was walking home from work late one afternoon.
One moment he says he loves me, the next moment he's asking for a divorce.
She never seems to know what she's doing from one minute to the next.

More examples

  • At one point Seeger fell afoul of the US government for his antiwar actions.
  • He managed to eke out a living one summer by selling drinks on a beach.
  • They met in Paris one enchanted afternoon in early autumn.
  • I suspected he wasn't telling me the truth, and one day I caught him out when I found some letters he'd written.
  • We met one day last year when we got talking in a bar.

one number, determiner (SINGLE)

B2 a single thing; not two or more:

Eat them one at a time (= separately).
I think we should paint the bedroom all one (= in a single) colour.
UK Do you think five of us will manage to squeeze into the one car?
(all) in one

C2 combined in a single person or object:

With this model you get a radio, CD player, and MP3 dock all in one.

More examples

  • With one blow of the knight's axe, he clove the rock in twain.
  • Only one competitor made a clear jump of the highest fence.
  • Don't let one little quarrel come between you.
  • I took one look at her and cracked up.
  • The canteen is the one thing I'll miss about work.

one number, determiner (ONLY)

B2 used when saying there is no other person or thing:

He's the one person you can rely on in an emergency.
This may be your one and only (= only ever) opportunity to meet her.
My final guest on tonight's show needs no introduction. Please welcome the one and only Michael Jordan!

More examples

  • The one thing that's certain is that prices will go up.
  • He was the one person to complete the test with no mistakes.
  • She's the one person I can trust around here.
  • It is the one thing I regret about my time at the company.
  • The one thing he's not prepared to compromise is his family's safety.

one number, determiner (UNKNOWN PERSON)

formal used before the name of someone who is not known:

Her solicitor is one John Wintersgill.

Idiom(s)

onepronoun

uk /wʌn/ us /wʌn/

one pronoun (ONE THING/PERSON)

A2 used to refer to a particular thing or person within a group or range of things or people that are possible or available:

I have a few books on Chinese food. You can borrow one if you want.
Which one would you like?
Please make a copy for everybody in the office and a few extra ones for the visitors.
"Which cake would you like?" "The one in the front."
French croissants are so much better than the ones we get here.
There were lots of people watching, and not one of them offered to help.
I've received no replies to my job applications - not a single one (= none).
Chris is the one (= the person) with curly brown hair.
not be one to do sth UK informal

to never do something:

I'm not one to criticize other people, as you know.
be one for sth informal

to like something very much:

I've never been one for staying out late.
He's a great one for the ladies.

More examples

  • That's one classy vehicle you've got there.
  • You can always tell a real bow tie from one that clips on.
  • She's written five books, and every one a cracker.
  • Mrs. Wilson is one of our regular customers.
  • I really must get a new jacket - this one's starting to go at the elbows.

one pronoun (COMPARISON)

used to talk about one person or thing compared with other similar or related people or things:

They look so similar it's often difficult to distinguish one from the other.
You may have one or the other, but not both.
Crime and freedom are inseparable. You can't have one without the other.

More examples

  • During the night, he had rolled from one side of the bed to the other.
  • The two cultures were so utterly disparate that she found it hard to adapt from one to the other.
  • If I have to listen to something I don't understand, it just goes in one ear and out the other.
  • The two sisters are so similar that it's almost impossible to tell one from the other.
  • This film begins where the other one leaves off.

one pronoun (ANY PERSON)

C1 formal any person, but not a particular person:

One has an obligation to one's friends.
One ought to make the effort to vote.

More examples

  • One's primary responsibility is to the legal system.
  • One must not assume from this that the defendant is guilty.
  • I wondered whether there might, after all, be some truth in the old chestnut that one's school days are the happiest of one's life.
  • Yoga is said to restore one's inner equilibrium.
  • Spending time with one's family is never an unalloyed pleasure.

(Definition of “one” from the Cambridge Advanced Learner’s Dictionary & Thesaurus © Cambridge University Press)

"one" in American English

See all translations

onenumber

us /wʌn/

onepronoun, adjective [ not gradable ]

us /wʌn/

one pronoun, adjective [ not gradable ] (SINGLE)

not two or more:

There are too many of us to fit in just one car.

one pronoun, adjective [ not gradable ] (PARTICULAR THING/PERSON)

used to refer to a particular thing or person within a group or range of things or people:

There are lots of flavors – which one would you like?
He advised workers around him, especially the younger ones, to be patient.
Kayla is the one with dark brown hair.
Make sure the ones that we've got there do what you want them to do.
She is one beautiful woman (= she is very beautiful).
Why don’t we meet for lunch one day next week?
one of

To be one of a group of people or things is to be a member of that group:

It’s one of the most popular songs.

oneadjective [ not gradable ]

us /wʌn/

one adjective [ not gradable ] (ONLY)

used when saying there is no other person or thing:

He’s the one person you can rely on in an emergency.

onepronoun

us /wʌn/ fml

one pronoun (ANY PERSON)

any person, but not a particular person:

One ought to make the effort to vote.

(Definition of “one” from the Cambridge Academic Content Dictionary © Cambridge University Press)