Meaning of the word number-one in English

What does number-one mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

number-one

US /ˌnʌm.bɚ ˈwʌn/
UK /ˌnʌm.bə ˈwʌn/

Noun

yourself and no one else:

Example:
Frank is completely selfish - he only cares about number one.