Refers to points along the horizontal and the vertical axes of the computer screen, usually starting in the lower-left corner of the screen. Each pixel (the colour dots that make up the screen display) on the display screen has a location on the map of the screen that identifies it to the programmes that make the screen addressable (meaning the mouse can tell where it is on the screen and let the application know). Generally, the x-coordinate is the number of pixels going across the screen and the y-coordinate is the number of pixels going up the screen. When the pair intersects, that intersection represents a specific location on the screen.