A milling cutter is a rotary cutting tool used in a milling machine to remove material from a workpiece through a process called milling. Unlike drilling, where the tool advances along its rotational axis, in milling, the cutter is typically moved perpendicular to its axis, allowing cutting to occur on its circumference and end. In essence, the milling cutter is the heart of the milling process, responsible for the precise and controlled removal of material to create the desired shape and finish on a workpiece.