A cummerbund is a wide, pleated sash worn around the waist, typically as part of formal attire. It is often made of silk or satin and is commonly seen in men's evening wear, especially with a tuxedo. The cummerbund serves both a decorative and functional purpose, helping to cover the waistband of trousers and providing a polished look. Traditionally, cummerbunds are worn with the pleats facing upward, which is believed to hold small items like tickets or a handkerchief. They come in various colors, but black and navy are the most popular choices for formal events.