The authors agree that the surname has its main cluster in Paularo, in the Udine area, within the region of Friuli-Venezia Giulia.

E. Rossoni proposes that the surname derives from a nickname based on the Friulian term blanz ("white"), which would have alluded to a physical characteristic of the ancestor, possibly premature greying.

E. De Stefani offers a more cautious view. He notes that the Blanzan are documented originally in Arta Terme at least from the end of the 15th century. He rejects the hypothesis of a connection with the female name Blanza derived from blanca, arguing that the phonological laws of Friulian do not allow that evolution: from blanca one could not obtain in Friulian the form blansa or blanza. Consequently, De Stefani considers that the motivation of the surname remains without a clearly supported explanation. He also mentions a variant, Blanzano, unknown in other Italian contexts, which appears sporadically in some localities of Styria (Austria), corresponding to families of Friulian origin who emigrated to that area.