Get really close to your monitor while its on and look at it, use a magnifying glass if you have to. See the little dots? with a higher resolution you have more of those dots or pixels thus making the picture look more clear and detailed I guess its hard to appreciate without seeing it yourself. As turkey said the numbers horizontal and vertical pixels, with a 1360x786 monitor you have 1360 pixels in a row horizontally and 768 pixels in a row vertically. 1360x768 gets you the total amount of pixels on the screen.