Where does “greek” come from?

Greek derives from Old English Grēcas, from Latin Graecus, from Ancient Greek Γραικός, ultimately from the root ǵerh₂- meaning to grow or age.

greek (English): Alternative letter-case form of Greek; To display...

Definitions

Step	Language	Word	Meaning
1	Old English	Grēcas	the Greeks; Greeks
2	Esperanto	kreko	teal
3	Latin	Graecus	Greek, Grecian, of or pertaining to the Greek...
4	Ancient Greek	Γραικός	Greek; a Graecian, a member of an ancient...
5	Ancient Greek	γραῖα	—
6	Proto-Indo-European	ǵerh₂-	to grow old, to mature

greek — Etymology, Origin & Word History | Etymology Explorer