Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
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?"
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.
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.