number one

a number one

Of the very highest caliber, standard, or quality. That was a number one performance last night.
See also: number, one

number one

1. adjective Top-rated, best, or foremost. Sometimes hyphenated. He's the number one salesman in the whole region, so you can definitely learn from him. I was really hoping that we wouldn't have to face the number-one team in the first round.
2. noun Oneself. In this usage, the term implies that one's top priority or concern is or should be oneself. Used especially with the phrase "look out for number one." You need to be careful in situations where there's a stampede toward an exit, because everybody is just looking out for number one.
3. noun, slang Urine or the act of urination. (Feces or the act of defecation is called "number two.") A: "Mommy, I have to go to the bathroom." B: "Number one or number two?"
See also: number, one
Farlex Dictionary of Idioms.

ˌnumber ˈone

(informal)
1 the most important or best person or thing: We’re number one in the used car business. He’s the world’s number one athlete.
2 (often disapproving) yourself: She doesn’t care about other people and their problems. She just looks after number one. Take care of number one and forget everybody else. That’s his philosophy.
See also: number, one
Farlex Partner Idioms Dictionary

number one

1. mod. top rate; best. (see also numero uno.) We heard the number one high school band in the whole state last night.
2. n. oneself. I don’t know who will pay for the broken window, but old number one isn’t!
3. n. urination; an act of urination. Jimmy made a mess in his pants. But don’t worry. It’s just number one.
See also: number, one
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • a number one
  • A number 1
  • number one with a bullet
  • number of things or people
  • a number of
  • a number of (something)
  • number off
  • a few
  • any number of
  • digit
References in periodicals archive
World number ones and defending champions Novak Djokovic and Naomi Osaka were named as top seeds for the US Open on Wednesday.Djokovic, who will be chasing a 17th Grand Slam singles title in New York next week, heads the men's field with Spain's Rafael Nadal seeded second.
On the singles chart, US pop star Ava Max is at number one with Sweet But Psycho for the third week running.
In 2015, Love Me Like You Do by Ellie Goulding hit number one on Valentine's Day.
"We beat number one, Caroline's number one, and win first grand slam so this dream is now reality.
This was also the year the band had their first of four Christmas number one singles, with I Wanna Hold Your Hand Picture: ARTHUR SIDEY
Divide has been a number one album for 18 non-consecutive weeks since then.
"Hopefully I can be number one one day and compare but for now I'd rather be 10 and win grand slams than be number one."
Cone has had his fair shares of ups and downs when it comes to being the number one, much like Ginebra's history.
R City featuring Adam Levine stayed in third with "Locked Away" with former number one, "Easy Love", by London-based DJ Sigala in fourth.
The song that was famously deprived of Christmas number one in 1984 by Band Aid.
QCan you cowboy Linda AI think The Story 1981 western Q Who has had the most British Christmas number ones? James Richardson, Perth A The honour goes to Paul McCartney.
Summary: Still holding a hammer, Number One rested one hand on his hip and smiled at his handiwork.
Summary: Robbie Williams's amazing week, a number one record and Xmas lights.
Heading the field will be current world number one Caroline Wozniacki, whose consistent play throughout 2010 was rewarded when she took over at the top of the rankings following her run to the title in Beijing.
NEW European Tour number one Martin Kaymer has revealed what is next on his wish list.