In the early 1880s, with the focus on his traveling circus, Barnum purchased a huge African elephant named Jumbo from the London Zoo. The elephant was a beloved creature in England, and its fame preceded it to America.
Jumbo's arrival in New York was a great event stage managed by Barnum. Thousands of people turned out to see the elephant. A year after the opening of the Brooklyn Bridge, Barnum paraded his elephants across the structure to demonstrate to the public that it was safe. Jumbo led the procession.
Jumbo toured with the circus for several years, and was killed in an accident in a railroad yard in Canada when it was struck by a locomotive. Barnum, typically, told a fanciful story that Jumbo had died while trying to protect a younger elephant from wandering near the train tracks.
Jumbo got his name from his keepers at the London Zoo, and it's apparently based in Swahili words. But thanks to Barnum's promotion, the word "jumbo" entered the English language and today we have everything from "jumbo drinks" to "jumbo jets."