E. De Stefani maintains that this surname arose as a shortened form of the given name Odorigo, introduced into Friuli from Bavaria and the Tyrol. The Germanic base is othal ("homeland, patrimony", equivalent to the Old High German uodal), although in some cases the root auda ("wealth, possession") could also have intervened. The ending -ric reflects the Germanic word rich ("powerful, rich"). The devotion to Saint Ulrich —bishop of Augsburg between 923 and 973, the first saint canonised by the Catholic Church— favoured the diffusion of the name, of which the variant Ulderico is also attested. Over time, the appellative became a surname.

According to De Stefani, the surname is characteristic of Friuli, with special concentration in the Carnia —a mountainous zone of the north of Friuli, in the province of Udine—, where it is documented from the 16th century.

F. De Laurentiis proposes, on the other hand, other routes of origin. The surname could derive from the place name Dorigo, located in the province of Treviso; or have arisen as a nickname from the matronymic of Oria or Auria, with the sense of "son of Oria"; or from a gentilic linked to the place name Oria, present in various regions of Italy.