Where does “Giangregorio” come from?

Giangregorio (Italian) comes from Italian Gregorio, from Latin Grēgorius, from Ancient Greek Γρηγόριος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

Ancestry of “Giangregorio”, step by step

Giangregorio traces back through two separate lines of ancestry.

via Italian Gregorio

Step	Language	Word	Meaning
1	Italian	Gregorio	Gregory
2	Latin	Grēgorius	—
3	Ancient Greek	Γρηγόριος	watchful, vigilant
4	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
5	Proto-Indo-European	-yós	Creates adjectives from noun or verb stems

via Italian Gian

Step	Language	Word	Meaning
1	Italian	Gian	part of compound given names such as Gianmarco or Gianluca; John
2	Italian	Giovan	—

Every word from Proto-Indo-European -yós →Every word from Ancient Greek -ῐος →Every word from Ancient Greek Γρηγόριος →