Casement

A casement is a type of window or part of a window set that is attached to its frame by one or more hinges at the side. They are used singly or in pairs within a common frame, in which case they are hinged on the outside. Casements are often held open using a casement stay. Windows hinged at the top are referred to as awning windows, and ones hinged at the bottom are called hoppers. Historically, casement windows were the most common type of window before the sash window was introduced and contain leaded glass—the glass panes held in place with strips of lead. The term casement is also used to describe the style of window itself which opens like a door. They provide a generous opening for ventilation and often deliver a superior seal compared to other types when closed, making them energy efficient. Casements can be made of a variety of materials including wood, metal, or vinyl, and are a popular choice in many architectural styles for their aesthetic flexibility and practical functionality.