Dutch oven and casserole are not necessarily the same thing. A casserole is a baking dish that is usually made of glass or ceramic. A Dutch oven, on the other hand, is a type of thick-walled cooking pot that is typically made of cast iron or ceramic. While you can use a Dutch oven to make a casserole, not all casseroles are made in Dutch ovens.
One key difference between the two is that a Dutch oven has a tight-fitting lid, while a casserole typically does not. This means that when you're cooking with a Dutch oven, you can control the amount of heat and moisture much better than with a casserole dish. If you're looking for a dish to make a casserole in, a Dutch oven is a great option.