A valance is a decorative piece of fabric that is hung across the top of a window or along the top edge of a curtain or blind. It is typically used as a finishing touch to a window treatment and adds a decorative element to the window. Valances can come in a variety of styles, such as swags, cascades, and cornices, and can be made from a wide range of fabrics, including cotton, silk, and linen. They can be used alone or paired with other window treatments, such as curtains or shades, to add a polished and finished look to the window.