A deleted scene is like a part of a movie or TV show that wasn't quite good enough or important enough to be in the final version. It's kind of like when you draw a picture and then decide to erase a part of it because it doesn't look quite right. The people who make movies and TV shows sometimes film extra scenes, but then decide to take them out later because they don't fit with the story or they make the show too long. So, when you hear about a deleted scene, that means it's something that was taken out of the final version and you wouldn't have seen it if you watched the regular show or movie.