tenoning machine - a machine employed for cutting tenons in wood, consisting generally of four saws, two running vertically together, and capable of adjustment sideways for the different thicknesses required, and two running horizontally to cut the shoulder, mortise - the counterpart of a tenon; a cavity or hole, usually rectangular in shape, cut in the surface of a piece of timber, etc., to receive the shaped end (called a ‘tenon’) of another piece