Yenisey River vs Yenisei River

Yenisey River and Yenisei River both are nouns.

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

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

Yenisey River and Yenisei River: 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, Yenisey.

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