The authors differ both on the geographical origin and on the etymology of this surname. E. Rossoni considers it proper to the Salento area —that is, the southernmost zone of the region of Puglia, in southern Italy—, with a presence in the Brindisi, Lecce, Taranto and Bari areas, and a lesser extension in Sicily, between the Ragusa and Syracuse areas. Rossoni proposes three possible etymologies: the Albanian name Jahja; the Latin name Iaia, documented in the Historia Naturalis of Pliny the Elder; and the Slavic term Dzaja, proper to Dalmatian families settled in Salento towards the end of the 10th century, when the so-called Schiavoni or Slavoni took refuge in that area fleeing Saracen persecution.

V. Blunda, by contrast, presents it as a Sicilian surname of dialect origin, derived from the word ggiàia, which designates the jay, a bird known for its showy plumage and its ability to imitate sounds. According to Blunda, the surname would have arisen as a zoomorphic nickname applied to a talkative person, a mimic, or someone with a strident voice.