When you watch a movie or play a game on a computer or TV screen, sometimes you might see two pictures shown on the same screen at the same time. This is called a split screen. It's kind of like sharing a piece of paper with your friend and drawing your own picture on each half.
In computer graphics, a split screen is created by dividing the screen into two or more parts, and each part shows a different image or video. So, instead of seeing one full screen picture, you see multiple smaller pictures on the same screen.
Split screens are often used in video chat applications when you want to see both the person you're talking to and yourself at the same time. They are also used in games that allow for split-screen multiplayer, so that two players can play together on the same screen without having to share a controller.
Split screens can be split vertically or horizontally, meaning the screen can be divided in half either up/down or left/right. Different split screen styles can be used depending on the task at hand. For example, a vertical split screen might be used in a video editing program so you can see two different video clips side by side to compare them.
In short, a split screen is a way to show multiple pictures on the same screen at the same time, by dividing the screen into two or more parts. It's often used for video chats, gaming, and video editing.