F. Miranda notes that the surname could derive from a dialectal byname of varied meaning: it may be equivalent to "strange", referring to one who is outside the kinship, or to "outsider, foreigner", alluding in all cases to a quality attributed to the first bearer, whose exact origin is unknown.

V. Blunda specifies that the etymon is the Sicilian dialectal word strànu, with the sense of "extravagant, singular", and that as a surname it could have originated in a nickname applied to someone known for their particular manners or for departing from common customs.

Both authors agree in characterising it as a typically Sicilian surname of dialectal origin. Miranda adds that it is especially frequent in the eastern part of the island —in the Catania, Messina, Syracuse and Ragusa areas— and also present in the Palermo, Agrigento and Enna areas. He further notes that, through the various migratory phenomena, the surname later spread to numerous regions of the Italian peninsula, among them Lazio, Lombardy, Calabria, Piedmont, Veneto, Campania, Liguria, Emilia-Romagna and Tuscany.