This article explains what is meant by VGA

VGA: Video Graphics Adapter. A card with character generator and an array of microprocessors that translate bit information from the computer into displayable video signals for the monitor. These cards comply with various standards that determine the nature of the quality of the display. 

VGA, introduced in 1987, was the first analog card. It offered still higher resolution than enhanced graphics adapter (EGA) - 640 x 480 pixels for graphics and 720 x 400 pixels for test - and a color palette of 256 colors. VGA could also emulate EGA and color/graphics adapter (CGA). 

Super VGA (SVGA), devised by VESA in 1989, offers a resolution of 800 x 600 pixels.

XGA-8514A, introduced by IBM in 1990, offers a resolution of 1024 x 768 pixels (interlaced) and a color palette of 256 colors. 

Extended VGA (XVGA), introduced by VESA in 1991, offers a top resolution of 1024 x 768 pixels (non-interlaced) and a refresh rate significantly higher than that of IBM's XGA-8514A.

High-End Graphics Adapters, introduced in the late 1990s for professional workstations, offer top resolutions from 1280 x 1024 to 1600 x 1280 horizontal line frequencies up to 90kHz, and bandwidths up to 200 MHz.