E. Rossoni notes that this surname is proper to the Salento area —that is, the southernmost zone of the region of Apulia, in southern Italy—, with a presence especially in localities of the Lecce area such as Sannicola, Tuglie, Parabita and Matino, besides secondary nuclei in Rome, Livorno and Milan originated by emigration. He proposes two possible etymologies: the initial reduction of the feminine name Rosaria, or else a derivation from the Greek name Rhianus, a well-known epic poet of the 3rd century BC.

G. Rohlfs offers a different and more precise interpretation, both geographically and linguistically. For Rohlfs, it is a surname of Greek-Byzantine origin, documented in the provinces of Brindisi, of Taranto —in localities such as Grottaglie— and, with greater diffusion, in the Lecce area, where it appears in Collepasso, Cutrofiano, Parabita, Sogliano, Soleto, Tuglie and other localities. Its etymon would be the term ría from Greek (the Grecanic dialect spoken in the Grecìa Salentina), with the meaning of "king," derived from the Late Greek rēgas. Rohlfs further establishes a correspondence with the form riga, present in the Bova area, in Calabria, within the same Grecanic linguistic substrate.

Both proposals differ substantially: while Rossoni points to a possible reduction of a given name or to a classical Greek anthroponym, Rohlfs anchors the surname in the living lexicon of the Grecanic dialect of the Salento, with a concrete meaning and a detailed geographic distribution.