From Latin nuntius meaning 'messenger,' often associated with the Annunciation.
Nunzio comes from the Italian word nunzio, meaning messenger or envoy, itself borrowed from the Latin nuntius, the classical term for a herald or official bearer of news. The Latin root also gives English the word announce and the ecclesiastical title Nuncio — the Vatican's diplomatic representative to a foreign state. To name a child Nunzio is, in a sense, to name them after the role of communication itself, the act of carrying something important from one world to another.
The name is closely identified with southern Italy, particularly Sicily, Campania, and Calabria, where it has been common since at least the seventeenth century. Its popularity there is intertwined with devotion to the Annunciation — the moment the archangel Gabriel announced to Mary that she would bear the Son of God — and the name Nunzio (along with its feminine form Nunzia and the longer Annunziata) was traditionally given to children born around the feast of the Annunciation on March 25th. Saints named Nunzio are venerated in several southern Italian dioceses, reinforcing the name's devotional currency.
Nunzio migrated to the United States, Argentina, and Australia with the great waves of Italian immigration in the late nineteenth and early twentieth centuries, where it became one of those names that sits unmistakably within a specific cultural heritage — the kind that a Sicilian-American family might carry across generations even as surrounding names anglicized into Nino or Nick. Today it reads as warmly retro within Italian communities, a name that tastes of espresso and Sunday ragù, dignified without being stiff.