A bustier is a form-fitting piece of lingerie, which typically reaches down to the ribs or waist. It pushes up the bust while gently shaping the waist. A woman might wear a bustier as an undergarment/push-up bra under a low-backed dress.

A corset is an undergarment that is specially designed to support the bust and define the waistline. Corsets can be made of various materials such as leather or any kind of flexible material and then they are enforced with hard strips which are referred to as “boning”. Corsets are relatively small in size and generally only cover the area between the breasts and the hips.