A. Bongioanni notes that the surname derives from the Latin given name Aemygdius, of uncertain etymology, and that its use as a proper name was historically restricted almost exclusively to the region of the Marche. The author links this geographical distribution with the cult of Saint Emidius, bishop of Ascoli Piceno in the 4th century, whose feast is celebrated on 5 August.

E. Rossoni, on the other hand, proposes a different etymology: the surname would derive from a distortion of the Latin name Aemilius, probably borne by the founder of the lineage. Rossoni also admits, although with less conviction, a possible derivation from the archaic Sabine name Aemidius. The author places it as a very rare surname, of probable origin in Magna Graecia —the ancient denomination of the Greek colonies established in southern Italy—.