Display Resolution is what can qualify a monitor in computer science. It is the number of pixels displayed on a given surface. For example: a "640 by 480 display", which has 640 pixels from side to side and 480 from top to bottom (as in a VGA display), and therefore has a total number of 640 x 480 = 307,200 pixels or 0.3 megapixels, is what is meant by 640 x 480 display resolution.
The display resolution or display modes of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT) displays, flat-panel displays (including liquid-crystal displays) and projection displays using fixed picture-element (pixel) arrays.
It is usually quoted as width x height, with the units in pixels: for example, "1024 x 768" means the width is 1024 pixels and the height is 768 pixels. This example would normally be spoken as "ten twenty-four by seven sixty-eight" or "ten twenty-four by seven six eight".