1. (

• number_one

) a reference to yourself or myself etc.; `take care of number one' means to put your own interests first ;

2. (

• first ,
• number_one

) the first or highest in an ordering or series; "He wanted to be the first" ;

3. (

• first ,
• number_one ,
• number_ ,

) the first element in a countable series; "the first of the month" ;