F. Miranda notes that this surname derives from the Greek prótos, with the meaning of "first" or "the one who is ahead of all." In the labour and technical sphere, the term designated the chief workman in charge of the distribution and general inspection of the work. Its transformation into a surname could derive from the trade of proto magister —architect or director of a building work— or from the role of foreman exercised by the first bearer of the surname.

Miranda describes it as a surname diffused mainly in southern Italy —in particular in Campania, Sicily, Apulia and Calabria—, although also present in Lombardy, Lazio, Piedmont, Tuscany, Liguria, Emilia-Romagna and Veneto. In Sicily it is documented with a greater concentration in the Catania, Messina, Enna and Agrigento areas, and with a smaller presence in the Palermo and Syracuse areas.

G. Rohlfs agrees on the Greek origin and on the root πρῶτος ("first"), but supplies a specific historical perspective: he considers it a surname of Greek-Byzantine origin, present throughout Calabria, and interprets it as a reflection of the Byzantine presence in southern Italy and of the survival of the Greek lexicon in Calabrian onomastics.

P. Durante confirms the Greek origin of the surname and the same root protos, with the meaning of "first," without adding information beyond that of the previous authors.