Cummerbund
A cummerbund is a sash that wraps around the waist and is most commonly associated with formal men's clothing. However, some women's outfits do feature a cummerbund sash.
In addition, it is also a style of bodice for a woman's dress and was very popular in the 1950s. A cummerbund waist often features horizontal ruching or gathering around the waist and forms a separate section below the bust.