E. Rossoni notes that this surname derives directly, or through an affectionate form, from the Latin nomen Cassius, a personal name of the Gens Cassia. Its presence is concentrated mainly in Trieste, Rome and the region of Puglia, in the Foggia and Bari areas.

A. Bongioanni considers it a given name of Latin origin and highlights that in Tuscany the most frequent form is Casciano, also documented as a place name and surname —see San Casciano—. He also notes that San Cassiano was a martyr under the emperors Decius or Valerian, is the patron of Imola and his feast is celebrated on 26 March. In Venice he is known under the form San Cassan. Bongioanni adds that in surnames such as Cassi, Cassetti and Cassini the name Acacio may also converge.