SNED is a term used in carpentry and woodworking. It stands for 'shoulder, notch, edge, and drill, ' which are the four steps involved in creating a mortise and tenon joint. The first step, shoulder, involves cutting a shoulder on the end of one piece of wood. The second step, notch, involves cutting a notch in the other piece of wood. The third step, edge, involves cutting an edge on the shoulder of the first piece of wood. The fourth step, drill, involves drilling a hole in the notch of the second piece of wood. Together, these four steps create a strong and secure joint.