Yenisey River vs Yenisei

Yenisey River and Yenisei both are nouns.

Word	Noun	Adjective	Verb	Adverb
Yenisey River	Yes	No	No	No
Yenisei	Yes	No	No	No

As nouns, Yenisey River and Yenisei are synonyms defined as:

Yenisey River and Yenisei: a Russian river in Siberia; rises in mountains near the Mongolian border and flows generally northward into the Kara Sea

Other synonyms of Yenisey River include Yenisei River, Yenisey.

Yenisey River (noun)	Yenisei (noun)
a Russian river in Siberia; rises in mountains near the Mongolian border and flows generally northward into the Kara Sea	the Uralic language spoken by the Yeniseian
	a Russian river in Siberia; rises in mountains near the Mongolian border and flows generally northward into the Kara Sea