Lower Tunguska vs river

Lower Tunguska and river both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lower Tunguska	Yes	No	No	No
river	Yes	No	No	No

Lower Tunguska (noun)	river (noun)
a river that arises to the north of Lake Baikal and flows north and west to the Yenisei River	a large natural stream of water (larger than a creek)