"very large," 1897, Amer.Eng., in ref. to Jumbo, name of the London Zoo's huge elephant, sold Feb. 1882 to U.S. circus showman P.T. Barnum. The name is probably from slang jumbo "clumsy, unwieldy fellow" (1823), which itself is possibly from a word for "elephant" in a W.African language (cf. Kongo nzamba).