Answer:stopped dado
Step-by-step explanation:
The stopped dado is used when you want to conceal a joint. The stopped dado is usee for cases when you don't want to see the joint connection at the front of the finished project.In this case Instead of cutting the dado groove right through to the end of the material, it is stopped short mostly by about the same distance as the thickness of the material.
A notch is then cut off the end of the board that fits in the dado, which matches the length of the material left in front of the dado.