The authors differ on the origin of this surname. F. De Laurentiis proposes three possible etymologies: the first links it to the old personal name Borso, very widespread in the lineage of the Este; the second relates it to the place name Borso, frequent in Veneto; the third derives it from the noun borsa understood as "money, market, payments". De Laurentiis also mentions, as a rarer meaning, that of "shepherd's purse", that is, a herbaceous plant of the Cruciferae family, with an erect stem, whose shape recalls the bag where the shepherd keeps the salt for the animals.

V. Blunda, on the other hand, proposes a Greek origin from býrsa, "skin, leather", with the passage of the Greek upsilon to o. According to this author, the term designated the tanned material used in furriery and craftsmanship, and the surname would have functioned originally as a trade nickname applied to the ancestor devoted to tanning or to the making of leather objects, which later became a surname by family line. Blunda places this development in Sicily.