A bustier is that shapewear that clings to the wearer's waist, emphasizing their curves, pushing up their breasts and showing off cleavage. Bustiers usually have built-in bra cups to help outline and push up the bust. No wonder they were referred to as "long line brassieres" back in the day — in reference to their dual functionality of bra and shapewear.
The clearest difference between both pieces of clothing is that the corset holds your waist tight for better curves while the bustier pushes up your breasts to give them a boost, per Recollections. Corsets are often found guilty of bunching up the midriff a little too tightly, causing possible harm to internal organs, per E-Times. Bustiers are not that restrictive, per Parfait.
Also, while corsets can either be overbust or underbust, there is no such option for bustiers. This is because one of the bustier's primary functions is to support and push up its wearer's breasts. This design peculiarity means that when these two garments are placed side by side, they look very different.
Corsets have taken their place in the wheel of fashion trends, as corset tops, leather corsets and other forms of corsets worn as outerwear have grown more popular, particularly off the virality of shows like Netflix's "Bridgerton" (via Independent.)
