The authors agree that this surname derives from a nickname or trade name formed on the dialectal noun caruso or carusu, which designated the boy or lad employed in agricultural, pastoral work or in the sulphur mines, especially in Sicily. Over time, the term came to designate generically the young man in Sicilian speech, a sense it preserves to this day in the living dialect of the island.

V. Blunda specifies that the dialectal word carùsu presents a double documented meaning: "shaven to the skin" and "decayed". The most widespread sense is the first, since the carusi —young workers of the Sicilian sulphur mines— had their heads shaved for reasons of hygiene. F. Miranda adds possible etymons: the Latin cariosus ("decayed, smooth, bald, shaven"), carens usu ("lacking experience") and the Greek kara ("shaven head").

E. De Felice highlights that it is an extremely frequent surname in southern Italy, present among the first in order of frequency in cities such as Naples, Cosenza, Reggio Calabria, Messina, Catania and Palermo. Miranda confirms its predominance in Sicily, Campania, Calabria and Puglia, also noting notable presence in Lazio, Lombardy, Piedmont, Tuscany, Emilia-Romagna and Liguria.