A banana split is a dessert, made with a banana cut lengthwise (hence the name), topped with ice-cream and whipped cream, here's a more detailed recipe:

Cut the banana in half lengthwise and lay it on a long dish (which is usually called "boat"), with the inside of the banana facing up.
Put the 3 balls of ice-cream on the inside of the banana, then top the chocolate ice-cream with chocolate topping, the vanilla ice-cream with pineapple topping and the strawberry ice-cream with strawberry topping.
Spray the whipped cream on top, then sprinkle the crushed nuts, and finally add the maraschino cherry