Tenon

A tenon is a projection formed on the end of a piece of wood that fits into a corresponding cavity called a mortise to create a mortise-and-tenon joint. This joint is a fundamental method in woodworking and timber framing, valued for its strength, alignment, and ability to be disassembled when needed. By drawing the shoulders against the mortised piece, it resists twisting and shear forces.

Tenons come in several variants. A straight tenon has a rectangular cross-section that slides into the mortise. A haunched tenon includes an enlarged area, or haunch, near the shoulder to improve resistance to twisting. Joints can be through tenons, which pass completely through the mortised piece and are visible on the far face, or blind tenons, which do not extend through. A slip or loose tenon uses a separate short piece that fits into corresponding mortises on both pieces being joined.

Construction and fit are critical to joint strength. The tenon thickness is typically about one-third to one-half the thickness of the corresponding piece, with the mortise depth matching the tenon length. Tight shoulders and a snug fit reduce gaps, and glue is commonly used along with pins or wedges in traditional work. The mortise-and-tenon joint remains popular in furniture making, cabinetry, and timber framing due to its durability and alignment precision.

In anatomy, Tenon’s capsule (or Tenon’s fascia) refers to a protective connective tissue sheath surrounding the eyeball, illustrating the term’s separate medical usage. See also mortise and tenon, joinery types, and loose tenon.