The authors agree that this is a surname of toponymic origin, derived from the place name Reggio Calabria. E. Rossoni notes that the surname seems to be specific to Sicily and to the Reggio Calabria area, and that it would derive from that place name in its dialect variant.

F. Miranda broadens this origin, specifying that Reggio Calabria corresponds to the ancient Greek colony known as Ρηγιον, and that in the Calabrian-Sicilian dialect it is pronounced Riggiu, the form from which the surname would derive directly. He notes that the surname is diffused throughout the Sicilian territory, with a greater presence in the Agrigento, Palermo, Catania, Messina, Trapani, Caltanissetta and Enna areas, besides in Calabria —especially in the Reggio, Cosenza and Catanzaro areas— and in Lombardy, Piedmont, Lazio and Liguria.