leather-leder-deri-uncertain-etymology

an uncertain etymology case: 

 German Leder, English leather, Greek δέρμα (dérma), Latin tergus. 

I have a supposal:

Old Turkish: TERI: Skin, Leather (animal skin)

modern Turkish: deri

 

We see this old Turkish word in 

Irk Bitig (Old Turkish: 𐰃𐰺𐰴 𐰋𐰃𐱅𐰃𐰏 (Book of Omens) not later than 900 AD) 

We read: Tabışgan TERIsi üngüşüpen yügürü barmiş. TERI: Skin, Leather (animal skin),(modern Tr. deri)

Uzunbacak Adem

No certain etymology 

Irk Bitig

Indo European words for Leather