number-one
UK: ˈnʌmbə wʌn | US: ˈnʌmbər wʌn
adj. most important or highest in rank
adj. of the highest quality or excellence
n. (informal) oneself; one's own interests
The term "number-one" combines "number," derived from Latin numerus (meaning "count" or "quantity"), and "one," from Old English ān (meaning "single" or "first"). The phrase emerged in the 19th century to denote supremacy, likely influenced by ranking systems where "1" signifies the top position. Over time, it expanded metaphorically to describe personal priority (e.g., "looking out for number-one").
She's the number-one player on the team.
This restaurant serves number-one sushi in the city.
He always puts himself first—classic number-one mentality.
The song hit number-one on the charts last week.
In business, customer satisfaction should be your number-one priority.