Where does “Grech” come from?

Grech (Polish) comes from Maltese Grieg, from Sicilian grecu, from Romanian grec, from Latin Graecus, from Ancient Greek Γραικός, from Ancient Greek γραῖα, from Proto-Indo-European ǵerh₂- — to grow old, to mature.

Ancestry of “Grech”, step by step

Step	Language	Word	Meaning
1	Maltese	Grieg	Greek
2	Sicilian	grecu	the Greek language; Hellene, a male Greek person;...
3	Romanian	grec	Greek; Greek man
4	Latin	Graecus	Greek, Grecian, of or pertaining to the Greek...
5	Ancient Greek	Γραικός	Greek; a Graecian, a member of an ancient...
6	Ancient Greek	γραῖα	Graea, Boeotia; Greece
7	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 →