It’s a system on a chip… A system on a chip combines a CPU, GPU (graphics processor) and various interconnecting bits and bobs into a single product. It’s the kind of thing a company can buy and construct an entire product around, in a similar way to how a PC buyer might buy a barebones PC and build it out. The Tegra 2 is far from the first SOC, but for mobile hardware, it’s easily one of the most powerful. (via What Is Nvidia’s Tegra 2?)