Where does “endogamia” come from?

endogamia (Italian) comes from Italian endo-, from Ancient Greek ἔνδον, from Proto-Hellenic éndon, from Proto-Indo-European h₁n̥dóm, from Proto-Indo-European h₁n̥dó, from Proto-Indo-European h₁én — in.

endogamia (Italian): endogamy