Graduate school is like going to school again, but after you finish your first four years of college. It's a special school where you can get more education in a certain subject that you're interested in.
When you go to graduate school, you can study things like science, business, law, or even art. It's a lot like college, but it's more focused on one specific topic.
Graduate school can be really tough, but it can also be pretty cool. You get to meet new people who are interested in the same things as you, and you get to learn more about your favorite subject.
When you're finished with graduate school, you'll have a special degree that shows you really know a lot about that subject. It could help you get a really good job, or help you do research to make the world a better place!