The use of this as a given name in the modern United States probably has very little to do with the literary character but is instead a use of the African place name. Zaire was the official name of the large nation in the middle of Africa that is now once again "Democratic Republic of the Congo" between 1971 and 1997. The geographic name is derived from a Portuguese name for the Congo River, which itself was derived from the Kikongo word "nzere". The name is predominantly African-American in usage, like the use of other African place names such as Kenya. [noted -ed]There has also evidently been some confusion in the African-American community between Zaire and Arabic names like Zaahir and Zahir, leading to a variety of forms that seem to be intermediate between them, like Zyhir, Zyair, Zaheer, Zyeir, etc.
"Zaire" is derived from the Portuguese word "Zaire", which is an adaptation of the Kongo word "nzere" or "nzadi," which mean "the river that swallows all rivers."