Aspect ratio is the term used to describe the proportional relationship between the width and height of an image. For example, the aspect ratio of a traditional television screen is 4:3, which means that for every four units of width, there are three units of height. The aspect ratio of a widescreen television screen is 16:9, which means that for every sixteen units of width, there are nine units of height. The aspect ratio of a CD cover is 1:1.4, which means that for every one unit of width, there are 1.4 units of height. This aspect ratio is based on the dimensions of a standard CD jewel case.