Box Joinery
Notches give this connective method its strength
Box joinery (also referred to as box joint) primarily joins sides to create boxes, both large and small, including trunks, chests and drawers. Notches are cut to match in an interlocking fashion, increasing surface area to allow for more glue strength and requiring minimal (if any) fasteners. Box joinery also helps keep the parts square. Originally a highly functional form of joinery, it's now often used as a decorative furniture element.
The notches cut in box joints correspond to the thickness of the adjoining boards.
This bar showcases box joinery where the side meets the top. You can clearly see the interlocking boards at the corner.