A corset is a piece of clothing that was once worn by almost all women as underwear to give them a defined waist. Today corsets are worn as outerwear more for reasons of fashion. A lot of garments today that are described as 'corsets' are just imitation with a corset look, but don't actually shape the body. Corsets are not usually held shut by zips or buttons like other garments. They usually hook together at the front and are laced up at the back, as you can see in the picture.