Noun
(informal) The most important of a group.
Synonyms: see Thesaurus:important person
(informal) Oneself, especially one’s own interests.
In his business ventures, he always looks after numero uno.
Making checklists of things you're looking for in a person is the numero uno thing you can do to guarantee you'll be alone forever. Joseph Gordon-Levitt
Founded by Piero De Vitis in 1977 and still run by his nephew Fabio Angilé, the Osteria Numero Uno combines the charm of a family-run restaurant with urban sophistication; past customers include Gerhard Schroeder and Wim Wenders. Source: Internet
I have long felt that India’s strategic intent should be to be Numero Uno. Source: Internet