Which of the following best defines a “face mill”?

A face mill is specifically designed for milling flat surfaces. It incorporates multiple cutting edges arranged on a circular disk, allowing it to remove material efficiently from a workpiece to create a smooth, level surface. This makes it an ideal tool for operations that require high precision and a fine finish on flat areas of a component.

While other choices mention different functions like drilling or grinding, these do not accurately reflect the primary purpose of a face mill. Drilling precision holes is the function of a drill bit, not a face mill. Sharpening edges may pertain to other types of cutting tools but is not characteristic of a face mill's design or use. Lastly, grinding materials typically involves a different process and toolset altogether, focusing on abrasion rather than milling. Thus, the definition of a face mill aligns closely with its function of milling flat surfaces, making it the correct choice.