It is one of the most commonly used processes for machining custom parts to precise tolerances. Milling can be done with a wide range of machine tools. The original class of machine tools for milling was the milling machine (often called a mill).
The term milling is documented as entering the English language in 1511, but it undoubtedly goes back centuries earlier, referring to the ancient practice of grinding wheat or other grains into meal or flour between two stones.