Why hyphenated adjective " Nagorno-Karabakh "?

Example, the Republic of Nagorno Karabakh, the Nagorno - Karabakh conflict.

It comes from the Nagorno-Karabakh( Karabakh - the key word, Nagorno - dependent) .

And this adjective does not begin with the elements of the North( Severno-) , South( South) , East, West, Central.