The authors differ notably on the origin of this surname. A. Bongioanni relates it to the Italian word croce ("cross"), noting that the name was originally given as an attribute of Christian devotion to numerous saints "of the Cross", and that it could also have been imposed on those born on the day of the feast of the Finding of the Holy Cross. From this base, Bongioanni identifies a set of derived surnames —among them Crocetta, Crocette, Crosara, Crosetto and Crosio— common in northern Italy, as well as place names of the same origin distributed throughout the peninsula.

Bongioanni also distinguishes regional variants: the forms Crose and Crosilla are peculiar to the Veneto and to Friuli-Venezia Giulia; Crocetti and Crosetti, to Piedmont; and Cruciani, to central Italy.

For his part, V. Blunda proposes for the Sicilian sphere a completely different etymology: he derives it from the Greek crocèas, meaning "individual of yellow skin". According to this interpretation, the surname would have arisen as a descriptive nickname applied to an ancestor for the yellowish tone of his complexion, following the habitual patterns of the Sicilian nicknames of Greek origin based on physical traits of the bearer.

Both proposals are independent of each other and could reflect different origins according to the region of Italy considered.