We don't have synonyms for Congo River yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are long river and coco river.
(N) :
The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world by discharge volume, following the Amazon and Ganges rivers.
(N) :
The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world by discharge volume, following the Amazon and Ganges rivers.