The surname Grosso derives from the Italian adjective grosso, meaning "big", "sturdy" or "stout". According to E. De Felice, it is a surname of descriptive origin (related to physical appearance) or else apotropaic, that is, with a symbolic or protective function. It was used in the Middle Ages as a nickname to identify people of strong build, and was later fixed as a hereditary surname.

E. Rossoni broadens this reading by noting that the term grosso was applied not only to people, but also to animals or things of great size, volume or weight. He also recalls that grosso was the name of an important medieval coin in various Italian regions, which adds a possible economic or symbolic nuance to the term.

The derived forms such as Grossi, Grossini, Grosselli and Gros are documented especially in northern Italy. The plural form Grossi is one of the most widespread variants. Rossoni also mentions the presence of Grosselli in areas such as Trento, Lazio and Rome, and cites a document of 1154 in Milan in which the name Grossus appears, a medieval form related to this surname. Traces are likewise recorded in the Codice Diplomatico della Lombardia for the year 1191.

There are also regional variants such as Del Grosso, typical of Tuscany, or Ingrosso, with the prosthetic prefix in-, frequent in Campania and Apulia. Other forms such as Grossone, Grossotto, Grossini or Grosselli reflect the use of augmentative suffixes or dialect adaptations.

According to Rossoni, in Sardinia the variant Grussu is found, typical of the Oristano area (Mogoro, Masullas, Uras, Carbonia and Cagliari). This surname derives from the dialect term grussu or nussu, with the same meaning of "big" or "thick", related to the Latin grossus. In the Sardinian context, it could also refer to large livestock.

For his part, V. Blunda links the surname to the Latin grossus, in relation to crassus (from which the surname Grasso derives). He adds that this type of adjective also appears in other surnames such as Chiappone or Chiapponello, where it describes a person of sturdy build or slow movements.

Finally, L. Lastrico notes that Grosso shows a strong concentration in Piedmont, especially in provinces such as Turin, Cuneo, Alessandria and Biella, with a notable presence in localities such as Bra, Novi Ligure and Turin. It is also found in other Italian areas such as Rome, Genoa, Naples, Chieti, Foggia and Cosenza. The variant Grossi shows an equally broad diffusion across different regions of the country.

Conclusion

Taken together, Grosso and its variants constitute a typical Italian surname derived from a medieval physical nickname, with multiple regional developments and a wide diffusion. Its evolution reflects both the linguistic richness and the social practices of personal identification in medieval Italy.