The authors agree that the surname derives from the Greek personal name Agathòn ("good, virtuous"), linked both to the classical stock and to Christian tradition.

A. Bongioanni identifies it as a Greek given name and recalls that it is the name of six saints, among them Pope Sant'Agatone, who died in 683, celebrated on 10 January.

Bongioanni suggests that the three names Agata, Agatino and Agatone are the most likely origin of many surnames that at first sight would seem to derive from the word gatto ("cat"): Gatteschi or Agateschi, Gattelli and Della Gatta —the last a doublet of Dell'Agata—. He also considers that, most probably, the Piedmontese surnames Catone and Chiattone come from here, since in the Piedmontese Alpine dialects the guttural consonant is often softened, producing forms such as ciat, giat or ciaval.

V. Blunda, for the Sicilian variant, derives it from the same Greek etymon Agathòn. He recalls that the name was illustrious both in classical Athens —Agathon the tragedian, friend of Socrates and a central figure of Plato's Symposium— and in later ecclesiastical tradition. He notes that Sant'Agatone was a pope of Sicilian origin in the 7th century, which explains the spread of the name in island onomastics during the Byzantine period.