Simply defined 3D printing is the process of creating a three dimensional solid object from a digital model. Basically, its the same concept of printing as when you print word documents off your computer. The difference is that instead of paper you are using building materials like PLA or ABS plastics. Instead of getting a piece of paper you are getting an object based on your design.
Some of the top brand names for 3D printers are 3D Systems, MakerBot and FormLabs. For schools and businesses, there is the affordable, professional CubeX 3D printer which can print objects up to the size of a basketball. If you are looking for something smaller for your home (and more budget friendly), the Cube 3D printer might be right for you.