What is a tool for sharpening tools called?

A tool for sharpening other tools is commonly referred to as a "sharpener." This can include various types, such as whetstones, honing rods, or electric sharpeners, each designed for specific types of tools or blades. Some sharpeners are tailored for knives, while others may be used for tools like chisels or axes. Overall, the choice of sharpener depends on the tool being sharpened and the desired level of sharpness.