What is 21 x9?

21x9 is a aspect ratio commonly used in widescreen displays, movies, and video games. It refers to the proportion of width to height dimensions, where the screen is 21 units wide and 9 units high. It offers a wider and more immersive viewing experience compared to the traditional 16:9 aspect ratio. This aspect ratio is commonly used in ultrawide monitors and gaming displays. It is also known as the 21:9 aspect ratio.