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number one

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noun
  1. oneself, especially one's own well-being or interests: to look out for number one.
  2. a person, company, etc., that is first in rank, order, or prestige: Our team is number one.
  3. urination: used especially by or with reference to children.
adjective
  1. of the highest in quality, status, importance, etc.; first-rate: a number one performance.
  2. first in rank, order, or prestige: the number one book on the bestseller list.
Idioms
  1. make/do/go number one, Informal. to urinate: used especially by or with reference to children.

Origin of number one

First recorded in 1830–40
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for number one

Contemporary Examples

Historical Examples

  • "I've a very great mind to give you a number-one kicking," said Billy.

    The Jungle Book

    Rudyard Kipling

  • Not number-one jade, of course, but still jade, and of value.

    Civilization

    Ellen Newbold La Motte

  • You ought to be mighty proud because all men think you are a number-one musher.

    Smoke Bellew

    Jack London

  • You've got thirty tons of fuel—you want to find the compression ratio of the number-one firing-tube chamber—so what do you do?

    Stand by for Mars!

    Carey Rockwell

  • I guess you won't see such a number-one instep as yours any time on these effete old London side-walks.


British Dictionary definitions for number one

number one

noun
  1. the first in a series or sequence
  2. an informal phrase for oneself, myself to look after number one
  3. informal the most important person; leader, chiefhe's number one in the organization
  4. informal the bestselling pop record in any one week
  5. euphemistic the act or an instance of urination
  6. a haircut in which the hair is cut very close to the head with an electric shaver
adjective
  1. first in importance, urgency, quality, etcnumber one priority
  2. informal (of a pop record) having reached the top of the charts
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012