number one

American  

noun

number ones plural

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.

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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, to urinate: used especially by or with reference to children.

number one British  

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, chief

   he'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

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adjective

1. first in importance, urgency, quality, etc

   number one priority

2. informal (of a pop record) having reached the top of the charts

Other Word Forms

Noun Inflected Forms

• number ones
  plural

Etymology

Origin of number one

First recorded in 1830–40

Example Sentences

That was the number one objective: to recover consumption.

From The Wall Street Journal • Jul. 9, 2026

In doing so she became the first Welsh person to score a number one hit in the US.

From BBC • Jul. 9, 2026

But a four-minute radio version took the world by storm, with the ballad spending two weeks as UK number one, and four weeks in the US.

From BBC • Jul. 9, 2026

Launched with the silky, catchy single Swim, the album charted at number one in 26 countries, and has already appeared on multiple best of 2026 lists.

From BBC • Jul. 7, 2026

“Lesson number one: bring in a bucket of water each night for coffee in the morning.”

From "Hattie Big Sky" by Kirby Larson

Related Words

• champion
• winner