Joint groove is a type of woodworking joint that is created by cutting a groove into two pieces of wood and then joining them together. The two pieces of wood are connected using a DADO, which is a four-letter term for a slot or trench cut across the grain of wood, and a MORTISE, which is a seven-letter term for a cavity cut into a piece of wood to receive a tenon. Together, the DADO and MORTISE create a joint groove that is strong and secure.