E. Rossoni proposes that this surname would derive from a nickname originating in the Greek word hiereia ("priestess"), which would have designated families with a founding ancestress notable for her hieratic bearing or for being the wife of an Orthodox priest. Rossoni notes that Iaria is typical of the Reggio Calabria area, with a presence in localities such as Melito di Porto Salvo, Condofuri, Bova Marina, Roccaforte del Greco, Seminara, Bagnara Calabra and San Lorenzo. The related forms Iera, proper to the Catanzaro area, and Ieria, extremely rare and likewise linked to the Reggio Calabria area, share a probable common root.

P. Durante confirms the Greek origin of the surname and specifies the etymological base: the term hierós, in its Doric form hiarós, whose meaning goes back to "sacred" or "priest", which converges with Rossoni's reading of the semantic link to the Orthodox religious sphere.