The authors agree that it is a surname of toponymic origin, linked to the Italian word prato ("meadow"), present in numerous place names of the region of Friuli-Venezia Giulia.

E. De Stefani documents the surname from the middle of the 15th century, with greater concentration in Ovaro —in the Carnia, a mountainous zone of the north of Friuli, in the province of Udine— and extended presence in Ampezzo, Villa Santina, Enemonzo, Socchieve and Tolmezzo, as well as more sporadically in Valle di Cadore (province of Belluno), Trasaghis and the city of Udine. He notes that the origin could be connected with local place names such as the Prato del Pozzo in Socchieve or the Prât in Ciargne in Forni Avoltri, and points as a specific motivation to the place name Prato Carnico, a comune of the Val Pesarina.

E. Rossoni agrees on the toponymic origin and mentions as possible etymons Pasian di Prato and Prato Carnico, both located in the Udine area.