3D Printing is the process of turning 3D designs into physical objects. Software slices the design into layers which are then printed layer by layer on a 3D printer, allowing for unique and customizable items. Print runs can be small or large. Processes such as injection moulding can make thousands even millions of copies at a low cost.
The technical term for 3D Printing is Additive Manufacturing. However, most people refer to the process almost exclusively as 3D Printing.