Bighorn vs Bighorn River

Bighorn and Bighorn River both are nouns.

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

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

Bighorn and Bighorn River: a river that flows from central Wyoming to the Yellowstone River in southern Montana

Bighorn (noun)	Bighorn River (noun)
a river that flows from central Wyoming to the Yellowstone River in southern Montana	a river that flows from central Wyoming to the Yellowstone River in southern Montana