E. De Felice, E. Rossoni and F. De Laurentiis agree that the surname derives from spada ("sword"), as an occupational name designating one who made and sold swords or other similar weapons, or one who followed the profession of arms.

De Felice specifies that it includes the southern form spata, and also records spadaro —Sicilian and Calabrian spataru— as a designation of the trade. He adds that, for Spada, the base could also be someone who went armed with a sword or knew how to handle it well.

Rossoni notes that it is absolutely widespread throughout Italy, and derives it from the trade of maker or seller of swords, or from soldier.

De Laurentiis adds that it is widespread with high and medium frequency throughout Italy, and that the names spada and spadaro designated both one who made and sold swords and one who followed the profession of arms.

It is identified as a very old Milanese surname, going back to an ancestor who must have been an armourer specialised in making swords, or else someone so skilled with the sword that they became identified with it. An Albertus Spata of Milan is documented in 1196, who was a witness in the Duomo of Monza at the appointment of Ariprando da Rho as archbishop by Oberto da Terzago, bishop of Milan.