A cavity cut into a piece of timber, or other material, to receive something (as the end of another piece) made to fit it, and called a tenon. Mortise and tenon, made with a mortise and tenon; joined or united by means of a mortise and tenon; used adjectively. Mortise joint, a joint made by a mortise and tenon. Mortise lock. See Lock. Mortise wheel, a cast–iron wheel, with wooden clogs inserted in mortises on its face or edge; also called mortise gear, and core gear.
Origin: F. Mortaise; cf. Sp. Mortaja, Ar. Murtazz fixed, or W. Mortais, Ir. Mortis, moirtis, Gael. Moirteis.