The authors agree that Aurnia is a Sicilian surname, although they propose different origins.

E. Rossoni derives it from the name of the locality Contrada Brizza Aurnia of Modica, the probable area of origin of the founders of the lineage.

V. Blunda places it in the group of Sicilian surnames of dialectal origin, within the phytonyms, those derived from names of plants. He derives it from the dialectal word aùrnu, meaning "white poplar". As a surname it may have originated in a place name applied to someone who lived near a notable white poplar, a tree that grows on humid riverbanks and is distinguished from the black poplar (Albano) by the light colour of the underside of its leaves. He notes that both surnames coexist in Sicilian onomastics with the same phytonymic motivation.