one

adjective \ ˈwən \

Updated on: 19 May 2018

Definition of one

1 : being a single unit or thing

one day at a time

She is one year old.

2 a : being one in particular

early one morning

The Grand Canyon is one place I'd like to visit.

b : being preeminently what is indicated

one fine person

She is one tough teacher.

3 a : being the same in kind or quality

both of one species

"Puma" and "cougar" are different names for one animal.

b (1) : constituting a unified entity of two or more components

The combined elements form one substance.

(2) : being in agreement or union

am one with you on this

4 a : some 1

will see you again one day

b : being a certain individual specified by name

one John Doe made a speech

5 : only 2a

the one person she wanted to marry

See one defined for English-language learners

See one defined for kids

Examples of one in a Sentence

There is one minute left in the game.
I have a few one-dollar bills in my purse.
She is one year old.

Recent Examples of one from the Web

Decisions made by engineers today, in other words, will determine not how one car drives but how all cars drive.

— johannes himmelreich, BostonGlobe.com, "The everyday moral challenges of self-driving cars," 30 Mar. 2018
Decisions made by engineers today, in other words, will determine not how one car drives but how all cars drive.

— johannes himmelreich, BostonGlobe.com, "The everyday moral challenges of self-driving cars," 30 Mar. 2018
Decisions made by engineers today, in other words, will determine not how one car drives but how all cars drive.

— johannes himmelreich, BostonGlobe.com, "The everyday moral challenges of self-driving cars," 30 Mar. 2018
Decisions made by engineers today, in other words, will determine not how one car drives but how all cars drive.

— johannes himmelreich, BostonGlobe.com, "The everyday moral challenges of self-driving cars," 30 Mar. 2018
Decisions made by engineers today, in other words, will determine not how one car drives but how all cars drive.

— johannes himmelreich, Smithsonian, "The Ethical Challenges Self-Driving Cars Will Face Every Day," 27 Mar. 2018
Disappearance is efficient because one disappearance can intimidate many opponents.

— jason scheideman, Washington Post, "Egypt and Syria have been “disappearing” their citizens. This is why countries do it.," 9 May 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'one.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of one

Middle English on, an, from Old English ān; akin to Old High German ein one, Latin unus (Old Latin oinos), Sanskrit eka

NEW! Time Traveler

First Known Use: before 12th century

in the meaning defined at sense 1

See Words from the same year

one Synonyms

Synonyms

alone, lone, only, singular, sole, solitary, special, sui generis, unique;

Near Antonyms

divers, manifold, multifarious, myriad;

assorted, heterogenous, miscellaneous, mixed, motley, patchwork, promiscuous, varied;

perennial, recurrent, repeated;

incomparable, inimitable, matchless, peerless, unequaled (or unequalled), unmatched, unparalleled, unrivaled (or unrivalled), unsurpassable, unsurpassed;

distinct, distinctive, individual, separate;

nonce;

Other Number-Related Terms

jubilee, myriad, quarantine, score, twain

one

noun

Definition of one

1 : the first whole number above zero — see Table of Numbers

2 : the number denoting unity

3 a : the first in a set or series —often used with an attributive noun

day one

b : an article of clothing of a size designated one

wears a one

4 : a single person or thing

has the one but needs the other

5 : a one-dollar bill

— at one

: at harmony : in a state of agreement

— for one

: as one example

I for one disagree

See one defined for English-language learners

Examples of one in a Sentence

one, two, three, four, …
I don't have any ones. Can you break a five?
I'll be there at one.

Recent Examples of one from the Web

The obvious one is Yohander Mendez, another lefty, who pitched well over 4 1/3 innings Tuesday for Triple A Round Rock and can be recalled next week before Moore's turn would come up at home against the New York Yankees.

— jeff wilson, star-telegram, "Rangers Reaction: Beltre not interested in 'going home' just yet | Fort Worth Star-Telegram," 16 May 2018
Tommy Ahlquist, first an emergency room doctor and then a developer, decided to make his next foray a political one.

— cynthia sewell, idahostatesman, "GOP backs Brad Little for governor: 'Now it is time to turn our attention to November.' | Idaho Statesman," 16 May 2018
Unlike the Spire plan, this one won’t be heavily dependent on sales to foreign buyers, Bailey said.

— ryan ori, chicagotribune.com, "First look at two-tower plan for Spire site: 'There will not be a shot of Chicago that doesn’t have these buildings in them'," 15 May 2018
This June Hair Guide is an important one to me for a variety of reasons.

— michelle lee, Allure, "Allure Editor in Chief Michelle Lee on the Importance of Inclusivity in Beauty," 15 May 2018
The only requirements in Kentucky are that one be over 18 and have a valid driver's license.

— The Courier-Journal, "Archives: 1988 reports on bus safety after the Carrollton crash," 14 May 2018
The other one is an AVM, or arteriovenous malformation.

— deborah netburn, latimes.com, "Melania Trump had an embolization to treat a kidney condition. What is an embolization?," 14 May 2018
Each of the families had been told to remove life support before learning that their loved one was conscious.

— Houston Chronicle, "Chronicle coverage takes top honors in national APME awards," 14 May 2018
On the afternoon the three LSU seniors -- and redshirt junior Bryce Jordan -- were honored for Senior Day in their final SEC home game, each one was able to have at least one special moment in LSU's 7-3 win against Alabama to take the series.

— brody miller, NOLA.com, "LSU baseball beats Alabama to win series on Senior Day," 13 May 2018

Origin and Etymology of one

see ¹one

NEW! Time Traveler

First Known Use: before 12th century

in the meaning defined at sense 1

See Words from the same year

one Synonyms

Synonyms

buck, clam, dollar;

Related Words

greenback;

Other Number-Related Terms

jubilee, myriad, quarantine, score, twain

one

pronoun

Definition of one

1 : a certain indefinitely indicated person or thing

saw one of his friends

2 a : an individual of a vaguely indicated group : anyone at all

one never knows

b —used as a third person substitute for a first person pronoun

I'd like to read more but one doesn't have the time.

3 : a single instance of a specified action

felt like belting him one
—John Casey

See one defined for English-language learners

Using one as a Pronoun

Sense 2a is usually a sign of a formal style. A formal style excludes the participation of the reader or hearer; thus one is used where a less formal style might address the reader directly.

- for the consequences of such choices, one has only oneself to thank
- —Walker Gibson

This generic one has never been common in informal use in either British or American English, and people who start sentences with one often shift to another pronoun more natural to casual discourse.

- when one is learning the river, he is not allowed to do or think about anything else
- —Mark Twain

Use of one to replace a first-person pronoun—sense 2b—has occasionally been criticized. It is more common in British English than in American.

- I'm watching this pretty carefully and I hope that the issue will come up in the Lords and one may be able to speak about it
- —Donald Coggan

Examples of one in a Sentence

“I'll have an iced tea, please.” “I'll have one, too.”
Their dog died, but they plan to get another one.
“You should wear the blue one.” “The one with the stripes?” “No, the other one.”
I'd like to see the ring next to that one.
Which one did you like better?
He is the one who called the police.
That's one possible answer—but not the only one.
I would like to read more, but one doesn't have the time.

Origin and Etymology of one

see ¹one

NEW! Time Traveler

First Known Use: 13th century

in the meaning defined at sense 1

See Words from the same year

-one

noun suffix

Definition of -one

: ketone or related or analogous compound or class of compounds

lactone

quinone

Origin and Etymology of -one

International Scientific Vocabulary, alteration of -ene

ONE Defined for English Language Learners

one

adjective

Definition of one for English Language Learners

: having the value of 1
—used to refer to a single person or thing
—used before a noun to indicate that someone or something is part of a group of similar people or things

one

noun

Definition of one for English Language Learners

: the number 1
: a one-dollar bill
: one o'clock

one

pronoun

Definition of one for English Language Learners

: that person or thing
: someone or something that is a part of a particular group
: people in general : any person

ONE Defined for Kids

one

adjective \ ˈwən \

Definition of one for Students

1 : being a single unit or thing

There's one catch.

2 : being a certain unit or thing

He arrived early one morning.

3 : being the same in kind or quality

All the members of one class will sit together.

4 : not specified

We'll meet again one day.

one

noun

Definition of one for Students

1 : the number denoting a single unit : 1

2 : the first in a set or series

3 : a single person or thing

one

pronoun

Definition of one for Students

1 : a single member or individual

I met one of your friends.

2 : any person One never knows what will happen.

Learn More about one

See words that rhyme with one Thesaurus: All synonyms and antonyms for one Spanish Central: Translation of one Nglish: Translation of one for Spanish speakers Britannica English: Translation of one for Arabic speakers

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one

Definition of one

Examples of one in a Sentence

Recent Examples of one from the Web

Origin and Etymology of one

one Synonyms

Synonyms

Near Antonyms

Related Words

Other Number-Related Terms

one

Definition of one

Examples of one in a Sentence

Recent Examples of one from the Web

Origin and Etymology of one

one Synonyms

Synonyms

Related Words

Other Number-Related Terms

one

Definition of one

Using one as a Pronoun

Examples of one in a Sentence

Origin and Etymology of one

-one

Definition of -one

Origin and Etymology of -one

ONE Defined for English Language Learners

one

Definition of one for English Language Learners

one

Definition of one for English Language Learners

one

Definition of one for English Language Learners

ONE Defined for Kids

one

Definition of one for Students

one

Definition of one for Students

one

Definition of one for Students

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