one

adjective
\ ˈwən How to pronounce one (audio) \

Definition of one

 (Entry 1 of 4)

1 : being a single unit or thing one day at a time She is one year old.
2a : 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.
3a : 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
4a : some sense 1 will see you again one day
b : being a certain individual specified by name one John Doe made a speech
5 : only sense 2a the one person she wanted to marry

one

noun

Definition of one (Entry 2 of 4)

1 : the first whole number above zero — see Table of Numbers
2 : the number denoting unity
3a : 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

one

pronoun

Definition of one (Entry 3 of 4)

1 : a certain indefinitely indicated person or thing saw one of his friends
2a : 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

Definition of -one (Entry 4 of 4)

: ketone or related or analogous compound or class of compounds lactone quinone

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Synonyms for one

Synonyms: Adjective

alone, lone, one-off, only, singular, sole, solitary, special, sui generis, unique

Synonyms: Noun

bone [slang], buck, clam, dollar, smacker [slang]

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Using One as a Pronoun: Usage Guide

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

Adjective

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

Noun

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

Pronoun

“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.
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Recent Examples on the Web: Adjective

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, 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

Recent Examples on the Web: Noun

Older rocks are on the bottom, younger ones are on top. Erin Dimaggio, Smithsonian, "How Do Scientists Date Fossils?," 13 June 2019 And the one interesting thing about International is the possibility that H might secretly be terrible, a smirk in a suit failing upwards. Darren Franich, EW.com, "Chris Hemsworth and Tessa Thompson reunite for eerily bland Men in Black: International: EW review," 12 June 2019 The firm’s other investments include Blue Bottle, Peloton and Fitbit, and Mr. Callaghan sees consumers of those products as ones who would be interested also in Better Place trees. Nellie Bowles, New York Times, "Could Trees Be the New Gravestones?," 12 June 2019 Although the Soviet Union sent several landers to Venus, the ones that survived quickly succumbed to the planet’s harsh environment: the longest-lasting one persevered for a mere 127 minutes. Shannon Hall, Scientific American, "Venus, Earth’s Evil Twin, Beckons Space Agencies," 12 June 2019 For every one positive article about capitalism, there are 11 negative ones. Alan Murray, Fortune, "Marc Benioff's CEO Activism: CEO Daily," 12 June 2019 Maria is known as the responsible one who pushes her siblings to complete school work and can sense when something is wrong. Jose Arredondo, ExpressNews.com, "Sandoval quads set to make San Antonio history again," 12 June 2019 The proposed budget is about $5 million higher than the one proposed for the current fiscal year, which ends June 30. Steve Dreyer, Pomerado News, "Poway council to review tight budget for coming year," 12 June 2019 In ZIP codes where most residents make less than $40,000, the analysis found reverse mortgage foreclosure rates were six times higher in black neighborhoods than in white ones. USA Today, "Seniors were sold a risk-free retirement with reverse mortgages. Now they face foreclosure.," 12 June 2019

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.

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First Known Use of one

Adjective

before the 12th century, in the meaning defined at sense 1

Noun

before the 12th century, in the meaning defined at sense 1

Pronoun

13th century, in the meaning defined at sense 1

History and Etymology for one

Adjective, Noun, and Pronoun

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

Noun suffix

International Scientific Vocabulary, alteration of -ene

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Statistics for one

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Time Traveler for one

The first known use of one was before the 12th century

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More Definitions for one

one

adjective

English Language Learners Definition of one

 (Entry 1 of 3)

: 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

English Language Learners Definition of one (Entry 2 of 3)

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

one

pronoun

English Language Learners Definition of one (Entry 3 of 3)

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

one

adjective
\ ˈwən How to pronounce one (audio) \

Kids Definition of one

 (Entry 1 of 3)

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

Kids Definition of one (Entry 2 of 3)

1 : the number denoting a single unit : 1
2 : the first in a set or series
3 : a single person or thing

one

pronoun

Kids Definition of one (Entry 3 of 3)

1 : a single member or individual I met one of your friends.
2 : any person One never knows what will happen.

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More from Merriam-Webster on one

Rhyming Dictionary: 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

Comments on one

What made you want to look up one? Please tell us where you read or heard it (including the quote, if possible).

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