The authors agree that it is a toponymic surname that would derive from localities whose name contains the root piazza or piazzo, widely spread in the Italian peninsula. Among the possible place names there are Piazza Armerina (in the Enna area), Piazza Brembana (in the Bergamo area), Piazzola sul Brenta (in the Padua area), Piazza al Serchio (in the Lucca area) and Piazzatorre (also in the Bergamo area).

F. Miranda adds that the surname could go back to the Latin platea, with the sense of "market" or "parade ground", or to the Latin palatia, meaning "noble residence", in allusion to the Roman Villa of the Casale of Piazza Armerina. The surname presents multiple independent clusters of origin (ceppi), arisen in different regions without direct relation between them, with presence in Sicily, Friuli-Venezia Giulia, Lombardy, Piedmont, Tuscany and Lazio.

E. Rossoni notes that the cluster present in the Udine area could derive from some nearby locality, and that the Sicilian cluster would point especially to Piazza Armerina as the place of origin. Miranda adds that in Sicily the surname is documented in all the provinces, with greater concentration in the Palermo, Agrigento and Messina areas, as well as in localities of the Enna area such as Nicosia, Leonforte, Regalbuto and Calascibetta.