GPU (Graphics Processing Unit) - definition
The GPU (Graphics Processing Unit) is a specialized circuit designed to accelerate the image output in a frame buffer intended for output to a display.
GPUs are very efficient at manipulating computer graphics and are generally more effective than general-purpose CPUs for algorithms where processing of large blocks of data is done in parallel.
Modern smartphones are equipped with advanced embedded chipsets that can do many different tasks depending on their programming. GPUs are an essential part of those chipsets and as mobile games are pushing the boundaries of their capabilities, the GPU performance is becoming increasingly important.