corset

n.

A close-fitting undergarment, often reinforced by stays, worn to support and shape the waistline, hips, and breasts.

A corset is a garment worn to mold and shape the torso into a desired shape for aesthetic or medical purposes (either for the duration of wearing it, or with a more lasting effect).

The most common use of corsets is to slim the body and make it conform to a fashionable silhouette. For women this most frequently emphasises a curvy figure, by reducing the waist, and thereby exaggerating the bust and hips.