The authors agree that this surname derives from the Sicilian term failla, equivalent to the Italian favilla, meaning "spark" or "flash".

F. Miranda specifies that the ultimate root is the Latin favilla, a term already employed by Dante in the first canto of the Paradiso (I, 34): Poca favilla gran fiamma seconda. From that base derive the forms Faylla, Faglila, Failla and Faidda. From the Sicilian dialectal faidda comes also the verb faiddïari, "to give off sparks", used to describe the oven that has reached almost the temperature necessary to bake bread, according to the Sicilian Vocabulary of Piccitto.

E. Rossoni links it specifically to the nickname originated in that Sicilian term, underlining its clearly Sicilian character.

Miranda adds that the surname is spread in Sicily in all its provinces, with greater presence in the Ragusa, Syracuse, Trapani, Catania, Palermo areas and in the Enna area. It is also recorded sporadically in other regions such as Lombardy, Lazio, Piedmont, Tuscany, Emilia-Romagna and Veneto.