WordNet sense 1 (a major African river (one of the world's longest); flows through Congo into the South Atlantic):

Congo River, Zaire River

WordNet sense 2 (a republic in central Africa; achieved independence from Belgium in 1960):

Zaire, Democratic Republic of the Congo, Belgian Congo

WordNet sense 3 (a republic in west-central Africa; achieved independence from France in 1960):

French Congo, Republic of the Congo

WordNet sense 4 (black tea grown in China):

congou, congou tea, English breakfast tea