Adorable girls in hot corsets.

A corset is a garment worn to hold and train the torso into a desired shape for aesthetic or medical purposes (either for the duration of wearing it or with a more lasting effect). Both men and women are known to wear corsets, though this item was for many years an integral part of women's wardrobes.
Since the late 20th century, the fashion industry has borrowed the term "corset" to refer to tops which, to varying degrees, mimic the look of traditional corsets without acting as them. While these modern corsets and corset tops often feature lacing or boning and generally imitate a historical style of corsets, they have very little, if any, effect on the shape of the wearer's body. Genuine corsets are usually made by a corsetmaker and are frequently fitted to the individual wearer.