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adjective \ˈwən\

Simple Definition of one

  • : 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

Full Definition of one

  1. 1 :  being a single unit or thing <one day at a time>

  2. 2 a :  being one in particular <early one morning> b :  being preeminently what is indicated <one fine person>

  3. 3 a :  being the same in kind or quality <both of one species> 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. 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. 5 :  only 2a <the one person she wanted to marry>

Examples of one

  1. There is one minute left in the game.

  2. I have a few one-dollar bills in my purse.

  3. She is one year old.

Origin of one

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

First Known Use: before 12th century

Other Number-Related Terms

Rhymes with one




Simple Definition of one

  • : the number 1

  • : a one-dollar bill

  • : one o'clock

Full Definition of one

  1. 1 — see number table

  2. 2 :  the number denoting unity

  3. 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. 4 :  a single person or thing <has the one but needs the other>

  5. 5 :  a one-dollar bill

at one
  1. :  at harmony :  in a state of agreement

for one
  1. :  as one example <I for one disagree>

Examples of one

  1. one, two, three, four, …

  2. I don't have any ones. Can you break a five?

  3. I'll be there at one.

Before 12th Century

First Known Use of one

before 12th century

Other Number-Related Terms




Simple Definition of one

  • : that person or thing

  • : someone or something that is a part of a particular group

  • : people in general : any person

Full Definition of one

  1. 1 :  a certain indefinitely indicated person or thing <saw one of his friends>

  2. 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. 3 :  a single instance of a specified action <felt like belting him one — John Casey>

Usage Discussion of one

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

  1. I'll have an iced tea, please. I'll have one, too.

  2. Their dog died, but they plan to get another one.

  3. You should wear the blue one. The one with the stripes? No, the other one.

  4. I'd like to see the ring next to that one.

  5. Which one did you like better?

  6. He is the one who called the police.

  7. That's one possible answer—but not the only one.

  8. I would like to read more, but one doesn't have the time.

13th Century

First Known Use of one

13th century


noun suffix

Definition of -one

  1. :  ketone or related or analogous compound or class of compounds <lactone> <quinone>

Origin of -one

International Scientific Vocabulary, alteration of -ene

Seen and Heard

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


February 6, 2016

an official order, decree, or edict

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