What is the designation for a window rail that is positioned at the top?

The designation for a window rail that is positioned at the top is known as the top rail. This term specifically refers to the horizontal component that forms the upper edge of a window frame or sash, playing a critical role in the structural integrity and aesthetic appearance of the window. The top rail is essential for maintaining the window’s overall strength, as it helps to support the weight and stress placed on the window assembly while also providing a finished look.

Understanding the role of various window components adds to the knowledge necessary for architectural design and window construction. The other terms—such as bottom rail and side rail—refer to different sections of the window frame. The bottom rail is located at the lower edge, and side rails are positioned along the vertical sides. Each of these components has its own function and placement, but only the top rail is designated for the uppermost section of the window.