Stands for "Integrated Graphics Processor." An IGP is a graphics chip that is integrated into a computer's motherboard. The IGP serves the same purpose as a video card, which is to process the graphics displayed on the computer.
Integrated graphics processors take the graphics portion of the processing load off the main CPU. However, because IGPs are soldered onto the motherboard, their size is limited and they cannot use a dedicated fan to cool them, like some video cards do. For this reason, IGPs typically do not have the same performance as video cards, which may be attached to the computer's PCI or AGP slots. Because integrated graphics processors cannot be removed, they also cannot be upgraded like video cards can. However, because of their small size, IGPs are a good solution for laptop computers and entry-level desktop PCs.