Stands for "Video Graphics Array."
VGA is a computer graphics standard for displaying color graphics. The original specification supports a resolution of 640 x 480 at 16 colors or 320 x 200 at 256 colors. It also specifies the accompanying 15-pin VGA display connector.
IBM originally developed the VGA standard in 1987 for their PS/2 computer system, and the rest of the IBM compatible PC industry soon adopted it as the standard. Due to its long-lasting popularity, the 640 x 480 16-color display mode is still considered the lowest common standard that a computer supports. The development of more-powerful graphics cards resulted in extensions to VGA that allowed higher resolutions, like SVGA (800 x 600) and XGA (1024 x 768), as well as higher color depth up to 24-bit (more than 16 million colors).
The 15-pin VGA connecter was the standard connection between computers and monitors (as well as projectors, televisions, and other displays) from its introduction until its eventual replacement by DVI, HDMI, and DisplayPort. A VGA connection sends video signals from a computer to a monitor through an analog connection, making the video signal vulnerable to interference from other electronic devices and signal degradation over long cables.