E. Rossoni notes that Codecà is peculiar to the Cremona, Lodi and Milan areas, with significant presence also in that of Ferrara. He proposes two interpretations of its origin: the first links it to Codecasa —a surname concentrated in Lombardy, with probable origin in the area between the Milan and Lodi areas, and with a possible cluster also in that of Lucca—, of which Codecà would be a dialectal contraction; both forms would refer to the house where a knife-grinder lived or where whetstones were sold. The second interpretation connects it with the Lombard nobility from 1170 and derives it from the expression in Lombard dialect Co De Cà, with the sense of "the head of the house".

F. De Laurentiis proposes, on the other hand, that the surname was formed from a nickname composed of the northern word co, meaning "head", and the abbreviated term decà, attributed to persons whose ancestors had been beheaded. This hypothesis, of a nature clearly different from the previous ones, finds no support in the other sources consulted.