Relish: the shoulder of a joint

In everyday speech, relish means either a pickled condiment or a keen enjoyment of something. You relish a meal. You relish a challenge. The word carries pleasure.

In carpentry, a relish is a structural element of a mortise-and-tenon joint. The tenon is the projecting rectangular member that slides into a mortise, the cavity cut to receive it. A relish is the shoulder or step at the base of the tenon, or around its perimeter. This projection bears against the edge of the mortise opening and distributes stress across a wider surface. It stops the tenon from being pushed too far through the frame and prevents the joint from splitting under load. The relish strengthens the joint by increasing contact area and controlling how far the tenon can travel.

The term likely comes from an Old French word meaning a remainder or remnant, related to the verb "to leave behind." In joint work, the relish is what remains of the wood after the mortise is cut and the tenon is shaped. It is the material left standing at the shoulder. This etymology makes sense: the relish is literally a remnant of solid wood that serves a purpose.

The shift from "remainder" to "enjoyment" happened separately in the food world, where relish came to mean a flavourful addition to a meal. A relish in carpentry is not pleasurable in the abstract sense, but it is functional and valued for its role in keeping a frame rigid and square for years.