Video standard is a standard for video display adapters developed so that software developers can anticipate how their programs will appear on the screen. Industry groups define video standards, and they specify maximum screen resolution, which is measured by the number of pixels that can be displayed horizontally and the number of lines that can be displayed vertically; for example, the VGA standard defines a horizontal resolution of 640 pixels by 480 lines (640 X 480). See color depth, eXtended Graphics Array (XGA), HDTV, MCGA, resolution, SVGA, SXGA, VGA.