1number one or No. 1 noun
[noncount] 1 a : a person, thing, or position that is highest in rank : the most important person or thing in a group of people or things
▪ Who's number one in this office? ▪ Getting the car fixed is number one on my list of priorities. ▪ I'll tell you why we can't go on a vacation: number one, we can't afford it, and number two, we'll miss my sister's party. ▪ Two of their songs have gone to number one [=the highest rank] on the pop charts.
b : the most successful person or thing in a group of people or things
▪ Her movie is currently number one at the box office. ▪ When the goal was scored, the fans started to chant, “We're number one, we're number one.” 2 : your own happiness, health, or success : yourself
▪ I've been taking care of other people for too long. It's time for me to take care of number one. ▪ If you don't look out for number one [=if you don't take care of yourself], who will? 3 informal : liquid waste from the body : urine — used mainly by children or when speaking to children — compare number two
▪ Who's number one in this office? ▪ Getting the car fixed is number one on my list of priorities. ▪ I'll tell you why we can't go on a vacation: number one, we can't afford it, and number two, we'll miss my sister's party. ▪ Two of their songs have gone to number one [=the highest rank] on the pop charts.
b : the most successful person or thing in a group of people or things
▪ Her movie is currently number one at the box office. ▪ When the goal was scored, the fans started to chant, “We're number one, we're number one.”
▪ I've been taking care of other people for too long. It's time for me to take care of number one. ▪ If you don't look out for number one [=if you don't take care of yourself], who will?
