a notch, hole, groove, or slot made in a piece of wood or the like to receive a tenon of the same dimensions.

a deep recess cut into wood for any of several other purposes, as for receiving a mortise lock.

Printing . a space cut out of a plate, esp. for the insertion of type or another plate.

to secure with a mortise and tenon.

to cut or form a mortise in (a piece of wood or the like).

to join securely.

Printing .

to cut metal from (a plate).

to cut out metal from a plate and insert (new material) in its place.