A "green screen" is a special backdrop used in video production and photography. It is typically a bright green color, which makes it easy to remove in post-production. This technique allows filmmakers and photographers to replace the green background with different images or scenes, creating various visual effects. The process of using a green screen is called "chroma keying." When a subject is filmed in front of the green screen, software can identify and eliminate the green color, allowing for the insertion of new backgrounds. This method is widely used in movies, television shows, and even video games to create immersive environments.