Treenail

A treenail, also trenail, trennel, or trunnel, is a wooden peg, pin, or dowel used to fasten pieces of wood together, especially in timber frames, covered bridges, wooden shipbuilding and boat building. Many such buildings and bridges are still in use. Locust is a favorite wood when making trunnels in shipbuilding due to its strength and rot resistance and red oak is typical in buildings.