The authors agree that the surname originates in the medieval name of good omen Bellus, linked to physical beauty or to the wish that a son would grow up handsome. E. Rossoni specifies that the forms Dal Bello and Del Bello are patronymic, where the prefix Dal- or Del- is equivalent to "son of the". F. De Laurentiis, on the other hand, places the origin in Tuscany and notes that the base was first a nickname and then a given name.

According to Rossoni, Dal Bello is typically of the Veneto, with presence concentrated in the Treviso area —in localities such as Fonte, Vedelago, Asolo, Altivole and Castelfranco Veneto—, as well as in the Rovigo area and in the Padua area. Del Bello presents zones in the Bergamo area, between the Gorizia and Trieste areas, between the Ancona area and the Piceno, in Spoleto —Perugia area—, in Lanciano —Chieti area— and in Rome. The variant Delbello is typically of Trieste.