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.

1960s Three Piece Lace Cocktail Dress With Cummerbund

 1950s Dress With Cummerbund Waist