Lena River vs Lena

Lena River and Lena both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lena River	Yes	No	No	No
Lena	Yes	No	No	No

As nouns, Lena River and Lena are synonyms defined as:

Lena River and Lena: a Russian river in Siberia; flows northward into the Laptev Sea

Lena River (noun)	Lena (noun)
a Russian river in Siberia; flows northward into the Laptev Sea	a Russian river in Siberia; flows northward into the Laptev Sea