E. De Felice notes that this surname comes from a nickname based on the noun tornese —with southern dialectal variants turnese, turnise or turnisi—, the name of a coin minted originally in Tours, in central-western France, called in Old French tourneis. This coin was introduced in southern Italy by the Angevins and circulated there with various but modest values until the 19th century. De Felice adds that, in some cases, the surname may also reflect the demonym of Tours, likewise tourneis in Old French, adapted into Italian as Tornese.

E. Rossoni agrees on the origin from the nickname linked to the Angevin coin called tornese, and places the presence of the surname in specific zones of Italy: the variant Tornese is recorded in the Salento area —that is, the southernmost zone of the Apulia region, in southern Italy—, in the Reggio Calabria area, in Sicily and in lower Lazio; Tornesi appears in the Latina area; and Turnisi is practically singular.