A window sill, also referred to as the window bottom or window ledge, is a flat, shelf-like trim piece positioned at the base of a window. Window sills not only enhance the functionality of the window but also elevate the design of the entire element. Black granite window sills, once considered dull or mismatched, have now become a striking focal point, adding significant value to the overall project. As a key component of a building's structure, window sills play an essential role in securing the window frame in place.