The surname Biella and its variants —such as Bielli and Biello— present a mainly toponymic origin, linked to the locality of Biella in northern Italy. According to E. De Felice, it is an eastern Piedmontese and Lombard surname, frequent especially in Milan, formed from this place name, which indicates the geographical provenance of the lineage.

However, E. Rossoni proposes a broader interpretation, noting that although in some cases it can derive directly from the place name Biella, more frequently it would be linked to archaic forms of the medieval name Bellus. This name is documented, for example, in the 16th century in Clusone in the form Biello Fanzago, which shows a possible phonetic evolution from a personal name towards the surname.

From the point of view of distribution, E. Rossoni indicates that Biella is typical of Lombardy, while Bielli presents clusters in Lazio, the north of Milan and Varese, and in the Vercelli area; Biello, on the other hand, seems to concentrate in Vercelli and in Molise. Taken together, the various interpretations agree in pointing to a possible double origin —toponymic and anthroponymic— with a regional evolution that gave rise to various variants.