A sash is a type of window or door that incorporates moveable pieces of glass. In windows, several sashes are typically joined together to form a frame of glass panels, which are separated by thin metal strips called muntins. Sash windows were commonly found in Victorian and Georgian architecture. The design allows for the top sash to be slid down while the bottom sash is raised, facilitating ventilation during warmer weather. However, sash windows are not as common as casement windows due to their tendency to rattle in windy conditions, as well as issues with rot and distortion. Sashes can also be incorporated into cabinetry to create unique cabinet doors.