The authors agree that the surname derives from the medieval name Amatus, a continuation of the Latin Amatus, meaning "beloved" and, in the Christian era, "beloved or protected by God". E. De Felice and A. Bongioanni note that among the saints of this name are Saint Amato, patron of Saludecio, in the Rimini area, celebrated on 8 May, and another Saint Amato, bishop and patron of Nusco, in the Avellino area, who died in 1093.

F. Miranda adds that, thanks to its clear auspicious value, the name spread over time throughout Italy and also beyond the peninsula: in Spanish as Amado and in French as Aimé. Miranda also proposes a second hypothesis: the surname could derive from the Italianisation of the Arabic name Ahmad or of the better-known Muhammad in its aphaeretic form, both linked to the prophet Muhammad and derived from the Arabic verb hamida, "to praise, to commend", with the sense of "praiseworthy, worthy of praise".

As for its distribution, De Felice and Bongioanni indicate that the surname is widespread mainly in southern Italy, with maximum frequency in Naples and Sicily, although it also appears in central and northern Italy. Miranda specifies that the most consistent clusters are concentrated in Sicily and Campania, with relevant presence also in Puglia, Lombardy, Lazio, Calabria, Piedmont, Tuscany and Emilia-Romagna.