[DonRotolo]

CAD = Computer-Aided Design
CAM = Computer-Aided Manufacturing (or Machining)
CNC = Computer Numerical Control (Meaning something controlled by a computer).

You design it in CAD and make it using CAM to control a CNC machine (mill, lathe, whatever). Often you use CAM to create a file of "G-Code", which is then interpreted by the CNC to actually produce the part. G-Code is a standard, there are others. Google it.