A router is a tool used to rout out (hollow out) an area in the face of a relatively hard workpiece, typically of wood or plastic. The main application of routers is in woodworking, especially cabinetry.

It was a tool particularly used by pattern makers and staircase makers and consisted of a broad-based wooden hand plane with a narrow blade projecting well beyond its base plate gaining it the nickname Old Woman's Tooth. Although the original hand tool has a few advantages over the power tool equivalent and retains favour with some workers, since about 1960, it has all but been replaced by the modern spindle router, which was designed for the same work, although the first electric hand routers appeared in the years just after World War I.

Further refinement produced the plunge router, invented by ELU (now part of DeWalt) in Germany in the late 1940s. This is even better adapted for many types of work. Today, traditional hand-powered routers are often called router planes. Some workers[1] consider it to be the single most versatile woodworking power tool. Modern routers are often used in place of traditional molding planes or spindle moulder machines for edge decoration (molding) of timber.

Related to the router is a smaller, lighter version designed specifically for trimming laminates. It can be used for smaller general routing work. For example, with an appropriate jig it can be used for recessing door hinges and recessing lock face plates.