The surname Biadico, together with forms such as Biadigo or Biadego, is characteristic of the Lombard sphere and has an anthroponymic origin linked to family relationships. According to E. De Felice, it derives from a nickname formed from the Lombard term biàdegh (from the Latin aviaticus, from avus, "grandfather"), meaning "grandson". This type of denomination was frequent to identify a person according to their relationship with an ancestor, especially in contexts where the figure of the grandfather had social relevance.

Along the same lines, E. Rossoni interprets these surnames as indicators of descent, that is, "grandsons" of important ancestors, which could imply a certain family prestige. He also proposes a linguistic evolution from the medieval Latin term ablatichus (grandson), derived from avia ("grandmother"), which in the old Lombard dialect would have given rise to forms such as biàdich. This development reflects the phonetic transformation peculiar to the dialects of northern Italy.

From the geographical point of view, E. Rossoni notes that these variants are very rare: Biadico and Biadigo are concentrated in the Milan area, while Biadego is almost disappeared and seems to have had presence in the Venetian area. Taken together, both interpretations agree in pointing to an origin based on a family appellative, linked to descent and to medieval social structure.