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Etymology

The first European to come across the Zambezi River was Vasco da Gama in January 1498, who anchored at what he called Rio dos Bons Sinais (River of Good Omens), now the Quelimane or Quá-Qua, a small river on the northern end of the delta, which at that time was connected by navigable channels to the Zambezi River proper (the connection silted up by the 1830s). In a few of the oldest maps, the entire river is denoted as such. By the 16th century, a new name emerged, the Cuama River (sometimes "Quama" or "Zuama"). Cuama was the local name given by the dwellers of the Swahili coast for an outpost located on one of the southerly islands of the delta (near the Luabo channel). Most old nautical maps denote the Luabo entry as Cuama, the entire delta as the "rivers of Cuama", and the Zambezi proper as the "Cuama River".

In 1552, Portuguese chronicler João de Barros noted that the same Cuama River was called Zembere by the inland people of Monomatapa. The Portuguese Dominican friar João dos Santos, visiting Monomatapa in 1597 reported it as Zambeze (Bantu languages frequently shifts between z and r) and inquired into the origins of the name; he was told it was named after a people.

"The River Cuama is by them called Zambeze; the head whereof is so farre within Land that none of them know it, but by tradition of their Progenitors say it comes from a Lake in the midst of the continent which yeelds also other great Rivers, divers ways visiting the Sea. They call it Zambeze, of a Nation of Cafres dwelling neere that Lake which are so called." —J. Santos Ethiopia Oriental, 1609

Thus, the term "Zambezi" is after a people who live by a great lake to the north. The most likely candidates are the "M'biza", or Bisa people (in older texts given as Muisa, Movisa, Abisa, Ambios, and other variations), a Bantu people who live in what is now central-eastern Zambia, between the Zambezi River and Lake Bangweolo (at the time, before the Lunda invasion, the Bisa would have likely stretched further north, possibly to Lake Tanganyika). The Bisa had a reputation as great cloth traders throughout the region.

In a curious note, Goese-born Portuguese trader Manuel Caetano Pereira, who traveled to the Bisa homelands in 1796, was surprised to be shown a second, separate river referred to as the "Zambezi". This "other Zambezi" that puzzled Pereira is most likely what modern sources spell the Chambeshi River in northern Zambia.

The Monomatapa notion (reported by Santos) that the Zambezi was sourced from a great internal lake might be a reference to one of the African Great Lakes. One of the names reported by early explorers for Lake Malawi was "Lake Zambre" (probably a corruption of "Zambezi"), possibly because Lake Malawi is connected to the lower Zambezi via the Shire River. The Monomatapa story resonated with the old European notion, drawn from classical antiquity, that all the great African rivers—the Nile, the Senegal, the Congo, and the Zambezi—were all sourced from the same great internal lake. The Portuguese were also told that the Mozambican Espirito Santo "river" (actually an estuary formed by the Umbeluzi, Matola, and Tembe Rivers) was sourced from a lake (hence its outlet became known as Delagoa Bay). As a result, several old maps depict the Zambezi and the "Espirito Santo" Rivers converging deep in the interior, at the same lake.

However, the Bisa-derived etymology is not without dispute. In 1845, W.D. Cooley, examining Pereira's notes, concluded the term "Zambezi" derives not from the Bisa people, but rather from the Bantu term "mbege"/"mbeze" ("fish"), and consequently it probably means merely "river of fish". David Livingstone, who reached the upper Zambezi in 1853, refers to it as "Zambesi", but also makes note of the local name "Leeambye" used by the Lozi people, which he says means "large river or river par excellence". Livingstone records other names for the Zambezi—Luambeji, Luambesi, Ambezi, Ojimbesi, and Zambesi—applied by different peoples along its course, and asserts they "all possess a similar signification and express the native idea of this magnificent stream being the main drain of the country".

Other historical records show that the river was called Kasambabezi by the Tonga people, which means “only those who know the river can bath in it.” a name which is still in use to this day.

In Portuguese records, the "Cuama River" term disappeared and gave way to the term "Sena River" (Rio de Sena), a reference to the Swahili (and later Portuguese) upriver trade station at Sena. In 1752, the Zambezi Delta, under the name "Rivers of Sena" (Rios de Sena) formed a colonial administrative district of Portuguese Mozambique, but common usage of "Zambezi" led eventually to a royal decree in 1858 officially renaming the district " Zambézia ".