The authors agree that this surname derives from the given name Natale, which in turn comes from the Latin Natalis, a form derived from dies natalis ("day of birth"), and this from natus, participle of nasci ("to be born"). It is a name that established itself in the Christian sphere to designate, in origin, the day of the death of saints and martyrs —understood as a birth into eternal life— and which was later associated with the birth of Jesus, finally spreading as a baptismal name given to those born on Christmas Day.

E. De Felice notes that the variant with Nal- was formed in north-eastern Italy by lenition and subsequent disappearance of the intervocalic -d-, from the northern form Nadal(e). This explains surnames such as Nadali and Nadalini, proper to Veneto and, in part, to Emilia-Romagna. F. De Laurentiis stresses that the surname is found throughout Italy, although it is especially characteristic of north-eastern Italy, in the regions of Veneto, Friuli-Venezia Giulia and Trentino-Alto Adige, and in part of Emilia-Romagna.