This is the 4833rd most frequent Portuguese word.
favorito
Favorite; most preferred or liked.
Here, 'favorito' is used as an adjective to describe the noun 'livro', indicating the speaker's preference.
Meu livro favorito é 'O Senhor dos Anéis'.
My favorite book is 'The Lord of the Rings'.
In this question, 'favorito' is used as an adjective modifying the noun 'artista', inquiring about the listener's preferred artist.
Quem é seu artista favorito?
Who is your favorite artist?
Here, 'favorito' describes the noun 'sabor', expressing the speaker's favored choice of ice cream flavor.