Wikipedia defines Graphics Cards as: A video card, (also referred to as a graphics accelerator card, display adapter, graphics card, and numerous other terms), is an item of personal computer hardware whose function is to generate and output images to a display.

The term is usually used to refer to a separate, dedicated expansion card that is plugged into a slot on the computer's motherboard, as opposed to a graphics controller integrated into the motherboard chipset.

http://en.wikipedia.org/wiki/Graphics_card