This is the main difference that distinguishes CNC from waterjet cutting-the way they function and the extent of their functioning. CNC, or Computer Numerical Control, concerns and denotes the automatic control of virtually any kind of machine, including waterjet cutters. Waterjet cutting, however, refers to cutting materials using very high-pressure water, or sometimes a combination of water and abrasive materials, through metals, stones, or glass. If you’re comparing CNC machining versus waterjet cutting, keep in mind that CNC is a broader category, while waterjet cutting is just a very precise and versatile one.