E. Rossoni notes that the surname derives from the Greek name Ρόδιος (Ròdios) or from its Latin version Rhodius, which would refer to the origin of the ancestor on the island of Rhodes. He also points out the possibility —which he considers less probable— that it comes from the place name Rodio, a locality of the Salerno area. He records the transformation into a surname in Ostuni, in the Brindisi area, during the second half of the 18th century. Rossoni identifies Rhodio as an archaic form of Rodio, typical of Rome.

G. Rohlfs agrees on the Greek-Byzantine origin and likewise links it to the Greek surname Rodiòs, with the meaning of "native of Rhodes." Rohlfs places it geographically in Catanzaro and its province —Squillace and Crotone—, in the region of Calabria, and treats it as a graphic variant of Rodìo.

P. Durante confirms the Greek origin of the surname, likewise linked to Rhodes, without adding geographic or historical information.

As to the distribution of the related forms, Rossoni specifies that Rodio is typical of Apulia and is well diffused throughout the region, with a presence in the Lecce, Bari, Taranto and Brindisi areas, but with scarce implantation in the Foggia area. The variant Rodia presents, for its part, two areas of concentration: one in Campania —in the Avellino and Naples areas— and another in the Brindisi area.