E. De Felice notes that it is a Sicilian surname formed from the place name Furnari, a locality of the province of Messina.

F. Miranda broadens this origin and indicates that the surname derives from the medieval word fornarius or fornaro, which designated the trade of baker or holder of an oven, in turn coming from the Greek phournares ("baker"). He also notes that the place name Furnari, a municipality of the province of Messina, derives from the Latin Furnaris arx, that is, "fortress of Furnari".

According to Miranda, the surname is peculiar to eastern Sicily, with special concentration in the Catania area, although it is also present in the provinces of Palermo, Trapani, Caltanissetta and Agrigento, as well as in several municipalities of the Enna area. Outside Sicily, presences are recorded in Lombardy, Piedmont, Lazio, Campania, Liguria, Emilia-Romagna and Veneto.