The authors agree that this surname is of Friulian origin, with its epicentre at Moggio Udinese and a presence in the Udine area.

E. De Stefani documents the surname in the area from the end of the 15th century and notes that, given its brief character, the etymology is difficult to reconstruct. The hypothesis most supported by the author starts from the Friulian name Zuan ("Giovanni"), lengthened with the suffix -òt to give Zuanòt, from which the form Not would have arisen by truncation. This reading follows a Friulian pattern recognized also in other surnames of the region.

De Stefani also presents an alternative hypothesis: a connection with the personal name Notto, attested in Friuli from the middle of the 14th century, which derives from the Germanic Noto, in turn from the Old High German nôt, "need, urgency". This name would have functioned as a hypocoristic of Germanic compounds such as Notker, and the same element appears in Saint Notburga, venerated in the Tyrol and in Trentino-Alto Adige. In time it became a surname.

E. Rossoni, by contrast, proposes that the surname would derive from forms reduced by syncope and apocope of patronymics related to the name Antonio. Rossoni also records the variant Nut, practically unique, likewise Friulian and probably native to the Gorizia area.