The term 'hollowing tool' is a type of tool used in woodworking. It is also known as a router, which is a 6-letter word. A router is a power tool that is used to cut out shapes and hollow out areas in wood. It is typically used for making decorative edges, grooves, and other intricate designs. The router is a versatile tool that can be used for a variety of tasks, from creating intricate patterns to cutting out large pieces of wood.