CNC stands for Computer Numerical Control milling. This essentially means that the milling machine is moved and monitored by numerical computer control, rather than by hand.

CNC milling is a manufacturing process that uses a cutting tool mounted on a rotating spindle to selectively remove material from a raw substrate to get what we want. The workpiece is rigidly mounted on a table that moves or rotates in different planes, so the tool can work at multiple angles. Complex CNC milling machines can have 5 or more independent axes of motion to create more complex shapes or avoid moving the workpiece to a separate machine.