E. De Stefani proposes a toponymic origin for this surname: it would derive from Piano d'Arta, a locality of Carnia —the mountainous zone of northern Friuli-Venezia Giulia, in the province of Udine—, where it is documented from the end of the 15th century. De Stefani notes that this type of surname reflects a phenomenon frequent in Friuli, by which some families adopted as a surname the name of the place where they lived. At the end of that same century a documented migration to Tolmezzo is recorded. In Carnia the surname is now extinct, and its present-day presence in Campania does not imply a family continuity with that original stock.

E. Rossoni, on the other hand, proposes a different interpretation for the southern branch: the surname would be an ethnic form alluding to ancestors coming from localities whose name contains the root piana or piano, such as Piana d'Olmo and Piana del Mulino in the Campobasso area, Piana del Sele in the Salerno area, or Piana di Monte Verna in the Caserta area. According to Rossoni, the surname is today proper to southern Italy, with a greater concentration in the Naples area —especially in Giugliano in Campania— and in the Caserta area.