Adelfi, absolutely rare, would appear to be Neapolitan, Adelfio is decidedly Palermo. additions provided by Stefano Ferrazzi Adelfi, very rare, is found mostly in the Neapolitan dialect, Adelfio, more common than the previous one, has its epicenter in the Palermo area, both these surnames derive from the medieval name Adelfio or Adelfo, the Italianization of the Greek personal Adelphos, with literal meaning of brother; in this context, the term brother is more likely to be understood in the religious sense of a Christian, as shown by the use of the word adelphos in the Bible. As far as the surnames in question are concerned, therefore, these are the surnames of the personal names of the founders.
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