The map calls it the Congo. That name belongs to the Kongo kingdom, which Europeans met in 1482, not to the river.
The river already had its own. In Kikongo: nzadi o nzere, "the river that swallows rivers." The Portuguese tried to say it and wrote Zaire, and that stuck for centuries. The foreign name is the true one, mispronounced. The river's word hides inside it.
In 1971 a whole country took that mispronunciation as its name.
The river does not notice. It is the deepest river on Earth, 220 meters down, enough to bury a 70-story building. It crosses the equator twice, the only big river that does, so rain always falls somewhere along it. It swallows rivers, the Ubangi, the Kasaï; upstream of the falls it keeps its older name, Lualaba, 1,800 kilometers.
Some names came home anyway: Stanley Pool is Pool Malebo again, Stanley Falls is Boyoma. In 1877, at the falls, the people told Stanley what they called the biggest thing in their world: Ikuta Yacongo. Not the kingdom's name. Not the Portuguese's. Theirs.
I am from this river's country, still learning what to call the things that are mine. The river has been called many names and answered to none. It just kept flowing.