F. Miranda and G. Rohlfs agree that this surname has a Greek origin, derived from the term that designates the belly or the paunch. Miranda links it specifically to the Greek etymon coilìas (κοιλιαζ), meaning "swollen, pot-bellied", and notes that it would have arisen as a nickname referring to an ancestor with that physical characteristic, which over time became a surname. V. Blunda agrees with this etymology and with the interpretation of the descriptive nickname applied to bodily traits, a habitual characteristic in Sicilian surnames of Greek origin.

Rohlfs broadens the linguistic picture: he records the form cilìa with the meaning of "belly" in the Grecanic dialect of the Bova area, in Calabria, and relates it directly to the Greek κοιλία. He also notes that in Greece the form Kilias survives as a surname, which reinforces the continuity of the etymon in the Hellenic world. Rohlfs also considers this surname a sibling form of Cilèa, present in Cosenza and in Reggio Calabria, and characterises it as of Greek-Byzantine origin.

As for the geographical distribution, Miranda documents an extensive presence in Sicily: the Ragusa, Syracuse, Catania, Agrigento, Caltanissetta, Palermo and Enna areas concentrate most of the families with this surname. Rohlfs, for his part, notes its presence also in Calabria, especially in Cosenza and Reggio Calabria, in addition to confirming its Sicilian character.