This is the 5832nd most frequent French word.
costello
"Costello" is not a French word; it is typically a surname.
Here, 'Costello' is used as a proper noun referring to a named individual or performer.
Je suis allé au spectacle de Costello hier soir.
I went to Costello's show last night.
In this case, 'Costello' refers to a fictional character in a narrative.
Dans le livre, le personnage Costello est décrit comme mystérieux.
In the book, the character Costello is described as mysterious.
Here, 'Costello' is used to indicate the performer or creator of the musical piece.