The authors differ in the origin of the surname. According to what is recorded in Surnames in Italy, it would be a surname of anthroponymic origin, derived from the Germanic name Fridgair, meaning "friend of the spear", peculiar to the plain of Lombardy.

E. Rossoni, on the other hand, derives it from the Latin cognomen Frigenius, of which he offers as testimony an inscription in which a freedman named Quadratus dedicates a text to Sestius Munigalicus in the name of his patron Frigenius. Rossoni places it geographically in the Bergamo area, with particular presence in localities such as Treviolo, Bonate and Dalmine.