A. Bongioanni notes that the surname derives from the name of a Roman family of Latin origin, in turn related to the term petra ('stone'). He mentions that according to Fumagalli it would be a place name equivalent to 'of the stone', though he clarifies that the suffix -onius does not always have that value. The central historical referent of the name is Saint Petronius, bishop of Bologna between 430 and 450, patron of the city and celebrated on 4 October.

Bongioanni also documents regional derivations: in Piedmont, from the form Petronia arose the surname Trona, attested in the Mondovì area; from the form Petroniano derives Petrignani. With a change of the unstressed vowel, the name also gave rise to the variants Patrone and Patroni.

F. Miranda agrees on the link with petra and with the name Petrus, but adds that the surname may derive from the augmentative of that name or else from the Roman gens Petronia, of probable Etruscan, Umbrian or Sabine origin. Miranda also indicates that the surname is distributed across various regions of Italy, with a notable presence in Friuli-Venezia Giulia, Sicily —especially in the Catania area—, and also in Lazio, Piedmont, Lombardy, Veneto, Calabria, Apulia and Emilia-Romagna.