mortises
Tenons fit here
Mortises is the plural of mortise, a rectangular cavity cut into wood to receive a matching projection (a tenon) from another piece.
The mortise-and-tenon joint is among the oldest and strongest methods of joining wood, used in furniture and timber framing for millennia.
As a verb, to mortise is to cut such a cavity or to join pieces using this method: The craftsman mortised the rail into the post.