Orange River vs Orange

Orange River and Orange both are nouns.

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

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

Orange River and Orange: a river in South Africa that flows generally westward to the Atlantic Ocean

Orange River (noun)	Orange (noun)
a river in South Africa that flows generally westward to the Atlantic Ocean	a river in South Africa that flows generally westward to the Atlantic Ocean