A sill, in the context of architecture and construction, is a horizontal structural element that forms the bottom of a window or door frame. It serves as a support for the vertical components of the window or door, known as jambs, and helps to distribute the weight of the structure above it. Sills are often designed to project outwards to deflect rainwater away from the building, preventing water ingress and protecting the wall below. They can be made from a variety of materials, including wood, stone, brick, or metal, and are sometimes referred to as a windowsill or doorsill when specifying their application. In addition to their functional role, sills can also contribute to the aesthetic appeal of a building by providing a visual base for windows and doors and are often crafted with attention to detail and style.