[mor.tise] also mor.tice n [ME mortays, fr. MF mortaise] (15c): a hole, groove, or slot into or through which some other part of an arrangement of parts fits or passes; esp: a cavity cut into a piece of material (as timber) to receive a tenon--see dovetail illustration
[2]mortise also mortice vt mor.tised also mor.ticed ; mor.tis.ing also mor.tic.ing (15c) 1: to join or fasten securely; specif: to join or fasten by a tenon and mortise
2: to cut or make a mortise in