Terms of the Trade: What Is a Sill? Terms of the Trade: What Is a Sill?
You may have heard this term before in reference to doors or windows in a house. A sill is simply the horizontal part of a window or door's construction at the bottom of the frame. As far as doors are concerned, the sill is usually a flat piece of metal or wood that is easily walked over, whereas in windows, the sill can sometimes take on the form of a small ledge or shelf.