A corset is a stiff undergarment (although it is often worn as an outer garment) made with laces to fasten it tightly, commonly worn in former times to shape and support the body.
For body-modification purposes, corsets are worn in order to effect semi-permanent changes to the waistline and trunk area. While older corsets were often fashioned of whalebone and lace, newer models are often made of a combination of modern materials, including latex, rubber, leather, and cloth, with metal linkings and accessories surrounding a metal or plastic frame and bracing (modern fashion corsets tend not to be as strong, to many people's surprise).
Some corsets include a "bra" (overbust), and others are shorter underbust styles. When choosing a corset, it is essential that it be properly fitted and well made. Fashion corsets are not appropriate for permanent shaping, as they are simply not strong enough — even a well-made body modification corset usually lasts, at best, a year.