number one informalTranslate number one | into Italian Definition of number one noun 1a person or thing that is foremost or most important in an activity or area:businesses that were number one in their markets a record or book in a particular category that has sold the most copies in a particular time period: [as modifier]:the band’s first number-one album 2oneself:you must look after number one 3used euphemistically to refer to urine. 4a first lieutenant in the navy. adjective most important or prevalent; foremost:a number-one priorityPhrases number one, number two, etc. the shortest, or next shortest, etc., men’s cropped haircut produced with electric hair clippers. number one in other Oxford dictionaries Definition of number one in the US English dictionary
