E. De Felice classifies this surname as Jewish, of sporadic presence in the centre and north of Italy, formed from the place name Terni, in the Umbria region, seat of an old Jewish community dispersed between the 16th and 17th centuries. This dispersal explains why the surname spread beyond its place of origin, following the usual pattern of Italian Jewish surnames of toponymic base, which adopted the name of the city of provenance when settling in new communities.

E. Rossoni agrees on the Jewish origin and on the derivation from the place name Terni, but specifies that the surname spread mainly in Lombardy and Tuscany.