A dowel is a simple but clever wooden cylinder, usually smooth and round like a pencil but without the lead. Woodworkers and furniture makers use dowels to connect pieces of wood together invisibly from the inside. Instead of nails or screws showing on the surface, they drill matching holes in two pieces of wood, squeeze glue into the holes, insert a dowel, and suddenly the pieces are joined securely.

You've probably sat on furniture held together by dowels without knowing it. Many chairs use dowels to connect the legs to the seat. Bookshelves often rely on dowels to hold their sides and shelves together. The dowel acts like a hidden wooden pin that keeps everything aligned and sturdy.

Dowels come in different thicknesses, from the width of a toothpick to as thick as your thumb. Craftspeople choose the size based on how strong the joint needs to be. You might also see dowels used as axles in simple wooden toys or science fair projects because they spin smoothly. A dowel rod is just a longer version, and you can buy them at hardware stores and cut them to whatever length you need.