The term 'ballerina costume' can be broken down into two parts: a TUTU and other items. A TUTU is a type of skirt worn by ballerinas, typically made of tulle and often very short. It is usually worn over a leotard and tights, and may also include a bodice or other accessories. The other items that make up a ballerina costume vary depending on the style and performance, but may include a headpiece, ballet slippers, and other accessories.