Bundt Pan - Definition

A tube pan used for baking that has slped sides and makes a curved design on the top of the cake because of the curves on the bottom of the pan. 

When greasing a bundt pan, make sure to get oil or butter into all the crevices.

This is the bottom of the pan on the outside. The exact design may vary, but it generally has this "fluted" pattern. 

When the cake is in the pan, you don't see the pattern - it's on the bottom.

But when the cake is removed from the pan (by putting a plate or wire rack on top and flipping it over), the pattern is the top of the cake.