What is a table with a gap in the middle of the wooden slats called

The table with a gap in the middle of the wooden slats is called mortise and tenon. Mortise and tenon (sǔnmǎo), a major structural method of traditional Chinese architecture, furniture and other instruments, is a type of joint that combines concave and convex parts on two members. The projecting part is called a tenon (or mortise and tenon); the concave part is called a mortise (or mortise and tenon slot). It is characterized by the use of mortise and tenon to reinforce the object without the use of nails on the object.