An expansion card that permits graphics to be displayed on an analog computer. Generally, video adapters have their own BIOS, some memory to serve as the frame buffer and a RAMDAC.
An expansion card that plugs into one of your PC's expansion slots, allowing your software and your PC's monitor to talk with each other.
A board that plugs into a personal computer to give it display capabilities. The display capabilities of a computer, however, depend on both the logical circuitry (provided in the video adapter) and the display monitor. A monochrome monitor, for example, cannot display colors no matter how powerful the video adapter.