The authors agree that this surname derives from nicknames based on the medieval Italian term cito ("boy"), possibly to indicate that the founder of the lineage was very young or had a particularly youthful appearance. F. Miranda adds that, in the Tuscan dialect, citelli also designates a "calf" and, in a figurative sense, a little boy.

The surname presents independent clusters of origin in different regions of Italy. E. Rossoni notes a very small area between the Mantua and Modena areas, and another reduced presence in Sicily, in the Palermo and Catania areas. Miranda broadens this picture and indicates additional clusters in Lombardy, Veneto, Piedmont, Puglia, Trentino and Valle d'Aosta, in addition to mentioning the province of Syracuse among the Sicilian areas where the surname is known.

Rossoni also mentions the related forms Citello, practically unique and of probable Calabrian origin, and Citi, characteristic of Tuscany, especially in the Livorno and Pisa areas.