number one
Pronunciation:
noun
Definitions
The most important person, the one who is in charge.
Someone who is top of a ranking, who is ranked first.
Oneself, being considered foremost, as by an egoist.
Urine; urination.
adjective
Definitions
First; foremost; best, often used after its headword.
Example: Commuting to work is the number one reason to own a car.