The authors differ on the origin of this surname. E. Rossoni proposes two possible etymologies: a derivation from the French term and surname granjon ("small granary"), a place name very widespread in Savoy and in the Loire department, which would have reached southern Italy with the Angevins, or come directly from France to the Savona area; and another from augmentatives of the medieval name Grano. Rossoni identifies at least three independent clusters of presence: one in the Savona area, another in the Avellino area —specifically in the Bisaccia area—, and a third in south-western Sicily.

V. Blunda, by contrast, offers an explanation of a dialect character and exclusively Sicilian: the surname would derive from the word rànni, which in the local dialect designates maize, or Turkish corn. According to Blunda, the cultivation of maize, introduced from America during the period of Spanish rule, spread across the interior of the island, and the surname would have arisen as a nickname associated with the grower, or the habitual eater, of maize polenta.