A MORTISE FITTER is a skilled tradesperson who specializes in the installation of MORTISE and TENON joints. The term 'MORTISE FITTER' is derived from the combination of two words: 'MORTISE, ' which is a type of joint, and 'FITTER, ' which refers to someone who fits or assembles components. The TENON, which is the other half of the joint, is a protruding piece of wood that fits into the MORTISE. MORTISE FITTER is a job that requires precision and skill, as the joints must be cut and fitted accurately for the structure to be stable and secure.