In 1882, P.T. Barnum purchased what was allegedly the world's largest elephant for his traveling circus show from the London Zoo. This elephant was named Jumbo, as many elephants today are called as well. However, this jumbo is set apart because it was the first to hold that name. It was not named after a word for "big"; a word for "big" was named after it. That's all really cool, but where does the original name come from? Most definitely an African language, but which one, and what did it mean before? There are several theories proffered in response to this query. Some etymologists think that it was the word for "elephant", which would make sense; in the Kongo language, "elephant" is nzamba. Then again, it could be from Swahili jambo, meaning "thing", or Swahili jumbe, meaning "chief", or it could generally mean "clumsy person". And as for the phrase mumbo-jumbo, it seems to have come earlier, being first attested in 1738. It seems that the original mumbo-jumbo was a shaman chant, which got extended to "meaningless babble". However, since that too is most likely African in origin, it cannot be discounted from relation to jumbo. Philologizing non-Indo-European languages, especially ones without writing systems, is exceptionally difficult, so we really can't go much further than that.
Adam Aleksic has been described as the internet's sixth most famous etymologist. He loves writing about himself in the third person, he's a freshman at Harvard University, and he has disturbing interests in linguistics, vexillology, geography, board games, limericks, and law.
The Etymology Nerd