E. De Felice explains that the surname derives from the name of Christian thanksgiving and devotion Lausdeo, from the Latin phrase laus Deo —"praise be to God"—, given to long-awaited and much-desired children. The Italian form of that same name is precisely Laudadio, with an identical meaning. De Felice notes its presence in the centre and peninsular south, though sporadically.

E. Rossoni agrees on the meaning and motivation of the original name, though he attributes it to an auspicious tradition of probable Hebrew root, in the form Lausdei —"praised be the Lord"—, likewise reserved for much-desired children. Rossoni specifies that the form Laudadio has a main cluster in Lama dei Peligni, in the Chieti area, in the region of Abruzzo, with an additional presence in Apulia, especially in the Bari area. The variant Lausdei, by contrast, appears in isolated pockets of Ancona and Rome.

It should be noted that the connection with the Jewish world is not inconsistent with the Christian reading: expressions of praise to God with a similar structure were adopted in both traditions, and in the context of Italian Jewish surnames auspicious names of this kind are frequently found.