Where does “грек” come from?

грек (Mongolian) comes from Russian грек, from Old East Slavic грькъ, from Vulgar Latin graecus, from Ancient Greek Γραικός, from Ancient Greek γραῖα, from Proto-Indo-European ǵerh₂- — to grow old, to mature.

грек (Mongolian): Greek, Grecian

Definitions

Greek, Grecian

Ancestry of “грек”, step by step

Step	Language	Word	Meaning
1	Russian	грек	Greek
2	Old East Slavic	грькъ	—
3	Vulgar Latin	graecus	Greek
4	Ancient Greek	Γραικός	Greek; a Graecian, a member of an ancient...
5	Ancient Greek	γραῖα	Graea, Boeotia; Greece
6	Proto-Indo-European	ǵerh₂-	to grow old, to mature

Every word from Proto-Indo-European ǵerh₂- →Every word from Ancient Greek γραῖα →Every word from Ancient Greek Γραικός →