Nobody argues about what the name means. Plenty of towns argue about who earned it.
The "split" is literal. A peeled banana is cut lengthwise, and the ice cream, sauces and toppings go between the two halves. The dish grew out of the fruit-loaded sundaes of American soda fountains, and it is still served in a long glass dish called a boat.
The best-known origin story comes from Latrobe, Pennsylvania. In 1904, the account goes, David "Doc" Strickler, a 23-year-old pharmacy student working the soda fountain at Tassel Pharmacy, split a banana under three scoops of ice cream. He charged 10 cents, twice the price of an ordinary sundae, and students from nearby Saint Vincent College spread the word. In 2004 the National Ice Cream Retailers Association certified Latrobe as the birthplace, and a state historical marker followed in 2013.
The trouble is that the 1904 story rests on local memory and family accounts, not on any 1904 document. Wilmington, Ohio, has its own claim: restaurant owner Ernest Hazard is said to have invented the dish in 1907 to lure college students in during slow winter days. Boston, Davenport, Iowa, and Columbus, Ohio, have stories too.
Printed evidence complicates all of them. Food-history researcher Barry Popik found a Fitchburg, Massachusetts, newspaper advertising "Banana Split 10c" in October 1905. A trade magazine's report on a druggists' convention in Boston that autumn quoted a local soda dispenser praising the dish. Merriam-Webster also dates the term to 1905. That rules out Wilmington's 1907 date as the first, though it cannot prove or disprove Latrobe's 1904 one.
The ice cream historian Ed Marks has suggested the dish may have been invented independently in several places at once. Bananas were newly cheap, soda fountains were competing for novelty, and splitting the fruit was an obvious idea. Walgreens, whose early Chicago-area drugstores made it a signature dessert, is credited with spreading its popularity.
The word underneath, sundae, has a murky story of its own. It is first recorded in 1897, probably as a respelling of Sunday.