The authors agree that the surname refers to the personal name Dionìsio or Dioniso, which continues the Latin Dionysius, in turn an adaptation of the Greek Dionýsios, meaning "sacred, dedicated to Dionysus". Dionysus was the Greek god of the earth, fertility and vegetation, and his name is interpreted as "son of Zeus". Among the most venerated saints associated with this denomination stands out Saint Denis the Areopagite, converted by Saint Paul and apostle of the Gauls, whose feast is celebrated on 9 October.

A. Bongioanni and E. De Felice note that the surnames Dionisio, Dionisotti and Nisio are forms peculiar to Piedmont derived from this name. The forms Addonisio would have been constructed by adding an initial a- with a reinforcing function. Denisi and Donizetti reflect the influence of the French forms Denis and Denizet. Bongioanni adds that Danesi and Danesino could also be derivatives of this same name.

V. Blunda provides a perspective centred on Sicily: according to this author, the name designated the person consecrated to Dionysus and was preserved in the Byzantine hagiographic tradition through several saints with that denomination, which would have favoured its crystallisation as a surname in the sphere of Sicilian Greek.