The authors agree that this surname derives from a nickname designating the deacon, an ecclesiastical grade and religious function. F. De Laurentiis notes that the term took the southern form iacono, and in Sicilian and Calabrian iacunu. F. Miranda specifies that the deacon comes from the Greek diákonos and the Latin diaconus, with the sense of "servant", an assistant to the priest with functions of baptism, eucharist, preaching and charity. E. Rossoni adds that, in some cases, these could be contracted forms of the augmentative of the name Isacco, though he considers this possibility secondary.

As for its distribution, Miranda indicates that it is a Sicilian surname found in numerous regions of Italy, with its main core in Sicily —especially in the provinces of Agrigento, Catania, Caltanissetta, Palermo and Enna— and a presence also in Lombardy, Piedmont, Tuscany, Lazio, Campania, Liguria, Veneto and Emilia-Romagna. Rossoni confirms that Iacona is proper to Sicily, while Iacono shows specific areas in the Naples region and in southern Sicily.