A router bit is a cutting tool used with a power tool called a router. It shapes and cuts wood, plastic, and other materials by spinning at high speeds. Router bits come in various shapes and sizes, allowing for different types of cuts, such as grooves, edges, and decorative patterns. These bits are typically made from high-speed steel or carbide, which provides durability and sharpness. To use a router bit, it is inserted into the router, which guides it along the material. Proper selection and maintenance of router bits are essential for achieving clean and precise cuts in woodworking projects.