What is the primary use of a router in carpentry?

In carpentry, a router is primarily used to hollow out an area in wood. This tool is designed to create grooves, recesses, or profiles by removing material from the surface of the wood. The versatility of routers allows for precision in cutting complex shapes and designs, making them essential for various woodworking projects such as cabinetry, moldings, and decorative features.

While routers can also be used to shape edges of wood (which may seem similar to hollowing out), the primary purpose emphasized in this context is the act of hollowing out specific areas, allowing for intricate designs and joinery work. This distinguishing characteristic sets routers apart from other tools that may cut wood to size or sand surfaces, as those operations serve different functions in carpentry.