Cylindrical piece of wood used to fill a countersunk hole (typically to cover a screw head). Some plugs are meant to be decorative and stand proud of the surface, while others are intended to be sanded flush. A dowel can be used to make plug material, but keep in mind a dowel will show endgrain, while the rest of the board will show face grain, so the plug is more obvious. There are plug cutters on the market that enable you to cut your own face-grain plugs. This allows you to closely match the grain pattern for a nearly undetectable plug.