The authors differ as to the origin of the surname. E. Rossoni proposes two hypotheses: on the one hand, it could derive from Italianized modifications of the Provençal name Caleb; on the other, the southern nucleus could refer to the place name Caleo, a locality of the Cilento, in the Salerno area. Rossoni places the main nucleus in Carrara, with ramifications in Livorno and in the La Spezia area, specifically in Sarzana and Ortonovo.

V. Blunda maintains, on the other hand, a Greek origin, from Kalèos, linked to the root kal-, meaning "beautiful, handsome". According to Blunda, the name would have functioned initially as a personal name or nickname transmitted through the Byzantine influence in southern Italy, and became a surname with an Italianized spelling in Sicily.