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

Synonyms: Noun

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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 Drinkwater didn't make one appearance in a Chelsea shirt last season, whilst Bakayoko spent the season in Italy on loan at AC Milan. SI.com, "Chelsea Set to Entertain Offers for Out of Favour Midfield Pair Ahead of Transfer Deadline," 3 Aug. 2019 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 Drinkwater didn't make one appearance in a Chelsea shirt last season, whilst Bakayoko spent the season in Italy on loan at AC Milan. SI.com, "Chelsea Set to Entertain Offers for Out of Favour Midfield Pair Ahead of Transfer Deadline," 3 Aug. 2019 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 The Moonlight visionary has been sharing hints for months on his Vimeo, each one paired with Nicholas Britell’s soul-gripping score. Zoe Haylock, Vulture, "The Underground Railroad Teaser: All Aboard Barry Jenkins’s Long-Awaited Series," 25 Feb. 2021 Each one is soaked in an AHA formula and disposed of after use. Rebecca Deczynski, Health.com, "The Best Face Exfoliators for Soft, Glowing Skin, According to Dermatologists," 24 Feb. 2021 All these bodies are notes in an orchestra, each one a different sound. Christopher Borrelli, chicagotribune.com, "Artist Riva Lehrer paints portraits of people with disabilities — minus the mock heroics, the ‘freak show’ or the toxic staring," 24 Feb. 2021 Biden revives Obama policies – and each one hurts Americans. Jack Durschlag, Fox News, "Reporter questions State Department spokesman whether Biden taking credit for Trump accomplishments," 23 Feb. 2021 Not only have infections, hospitalizations and deaths been dwindling since a post-holiday spike in January, but two highly effective vaccines are finding their way into millions of American arms, and another one might be authorized soon. Elinor Aspegren, USA TODAY, "US deaths account for 20% of world's total of 2.4M; Johnson & Johnson plans 20M vaccine doses by end of March. Latest COVID-19 updates," 23 Feb. 2021 For visitors who collect national park passport stamps, the app has detailed photos of each one, along with information on where to get them. Jessica Poitevien, Travel + Leisure, "The National Park Service's New App Makes Planning a Visit Easier Than Ever," 22 Feb. 2021 Now, IceCube, the kilometer-wide neutrino detector nestled deep beneath the South Pole, has traced another one back to its far-flung birthplace: a supermassive black hole tearing a star to pieces in a galaxy 750 million light-years away. Daniel Clery, Science | AAAS, "Rare cosmic neutrino traced to star-swallowing black hole," 22 Feb. 2021 The cost for each one is about $2,000 and some of them could easily be removed from the plan. Phil Diehl, San Diego Union-Tribune, "City seeks $8.5 million grant for El Corazon Park," 21 Feb. 2021

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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Learn More about one

Time Traveler for one

Time Traveler

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

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Statistics for one

Cite this Entry

“One.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/one. Accessed 5 Mar. 2021.

Style: MLA
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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

Thesaurus: All synonyms and antonyms for one

Nglish: Translation of one for Spanish Speakers

Britannica English: Translation of one for Arabic Speakers

Comments on one

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