👉 In woodworking, a mortise is a keyhole-shaped hole that is drilled into a solid piece of wood to create a saw hole or an access point for a tool. The mortise is typically used in conjunction with a nut or bolt to secure the fastener to the workpiece and to allow it to rotate freely within the saw hole. Mortises are made from various materials such as steel, aluminum, or plastic, depending on the desired application of the tool.