"My sibling is Greek."

Translation: Kardeşim Yunan.

[Mirage20]

Benim kardeşim Yunanlı should be acceptable as well.

[AlexinNotTurkey]

Yunan means "Greek." Yunanistanlı means "from Greece." :) Yunanlı is not a word

[crystalliu647]

That makes a lot of sense thank you

[Selcen_Ozturk]

"yunanlı" is an incorrect usage

[Greys1405]

Why not benim kardeşim?

[LenaKPL]

Can we use Rum for Greek and Rumeli for Greece or it's historical? I heard many older Turkish people use it..