E. De Felice considers that the surname derives from original nicknames and trade names formed from frumento (wheat) and from formento, its dialectal variant peculiar to the Veneto and to Lombardy, together with its altered and derived forms. According to De Felice, the form Formenti has its main rooting in the Veneto and in Lombardy, while the form Frumento is documented in Liguria.

For its part, the presence of two farmers of Arosio identified as Frumentus and Cicer is recorded in documents of the municipal archive of Milan —between 1183 and 1216—, as well as a family of Palazzolo that in 1210 appears with the surname Frumentus. The most plausible hypothesis is that it is a baptismal name that over time became a surname.