The authors agree that this surname is of Greek origin and refers to the term that designates the deacon, a cleric of minor rank in the ecclesiastical hierarchy. P. Durante notes briefly that connection with the Greek diakon. V. Blunda specifies that the form comes from the Greek diàcos, an abbreviated version of the term for that ecclesiastical office, and that the surname arose as a nickname applied to an ancestor for his religious function; he documents it for Sicily.

E. Rossoni provides a different etymological nuance: instead of referring directly to the noun "deacon", he proposes that the surname would derive from a nickname originated in the Greek verb diakoneo, which means "to serve", alluding probably to the office performed by the founding ancestors. Rossoni places it geographically in Calabria, with presence in the Catanzaro, Cosenza and Crotone areas.