The authors agree that this surname derives from the medieval name Superanzo, later evolved into Soranzo, which in turn comes from the late-Latin name Superantius, based on the Latin term superus ("that which is above"), with the sense of "one who stands out, superabundant".

E. De Felice notes that the name functioned as a supernomen or auspicious signum of late antiquity, and is documented as a second name or surname in Chioggia in the year 912 and in Rialto in 1090 under the forms Superancio or Superantio.

E. Rossoni specifies that the earliest known mention corresponds to a Carolus Superantius, recorded around the year 549 in the chronological series of the tribunes of Rialto, in Venice. Rossoni also places the surname in two distinct areas: the Padua area and the Monfalcone area, in the Gorizia area. As a notable historical figure he mentions the Venetian doge Giovanni Soranzo, who ruled between 1312 and 1328.