number one
Americannoun
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number ones
plural
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oneself, especially one's own well-being or interests.
to look out for number one.
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a person, company, etc., that is first in rank, order, or prestige.
Our team is number one.
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urination: used especially by or with reference to children.
adjective
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of the highest in quality, status, importance, etc.; first-rate.
a number one performance.
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first in rank, order, or prestige.
the number one book on the bestseller list.
idioms
noun
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the first in a series or sequence
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an informal phrase for oneself myself
to look after number one
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informal the most important person; leader, chief
he's number one in the organization
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informal the bestselling pop record in any one week
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euphemistic the act or an instance of urination
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a haircut in which the hair is cut very close to the head with an electric shaver
adjective
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first in importance, urgency, quality, etc
number one priority
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informal (of a pop record) having reached the top of the charts
Other Word Forms
Noun Inflected Forms
Etymology
Origin of number one
First recorded in 1830–40
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
If you look into what Americans need: number one is more multifuel capability.
From The Wall Street Journal ● Oct. 6, 2026
"That's why it was interesting that walking was the number one reported exercise. It naturally provides opportunities to communicate."
From Science Daily ● Oct. 6, 2026
Sinner took the number one spot in April from Spain's Carlos Alcaraz, who returned from four months out with a wrist injury at the US Open in September.
From BBC ● Oct. 3, 2026
The Belarusian needed just 63 minutes to win her first match since losing her world number one ranking and her US Open crown to Elena Rybakina in September.
From BBC ● Oct. 2, 2026
"Stacy, will you please tell Mr. Johnson the number one reason why Shetlands are like goats."
From "Pony Problems: Nancy Drew and the Clue Crew, #3" by Carolyn Keene
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
