Congo vs Zaire River

Congo and Zaire River both are nouns.

Word	Noun	Adjective	Verb	Adverb
Congo	Yes	No	No	No
Zaire River	Yes	No	No	No

As nouns, Congo and Zaire River are synonyms defined as:

Congo and Zaire River: a major African river (one of the world's longest); flows through Congo into the South Atlantic

Other synonyms of Congo include Congo River.

Congo (noun)	Zaire River (noun)
a republic in central Africa; achieved independence from Belgium in 1960	a major African river (one of the world's longest); flows through Congo into the South Atlantic
a republic in west-central Africa; achieved independence from France in 1960
a major African river (one of the world's longest); flows through Congo into the South Atlantic