The authors agree that the surname is related to the nominal base Ariano, linked both to a place name and to a personal name.

E. De Felice specifies that the surname can be formed, especially in the south, both from the place name Ariano (in the province of Salerno, and Ariano Irpino, in that of Avellino) and from a variant of the name Adriano. He notes that it is widespread mainly in the Naples area and in Tuscany.

E. Rossoni derives it from the Latin name Arianus, documented in the year 311 AD with a Roman official who was governor of Thebes and, having converted to Christianity, was martyred and canonised.

Rossoni also proposes other hypotheses: a derivation from place names such as Ariano Ferrarese (Ferrara area) or Ariano Irpino (Avellino area), and another that derives Ariani from the Latin Ara Jani ("altar of Janus", the Roman god), which would indicate that the ancestor lived near a temple consecrated to that divinity.