Donburi is both a large and deep bowl made of clay, ceramic, or wood that has a lid on, and a dish - rice with a topping that goes inside this bowl. In modern Japan, even a lunchbox containing this type of meal is considered to be donburi.
According to some documents, it is a Japanese concept dating back to the 17th century when it was made with eel and eaten at the theatre. Soon, it became very popular because it was a meal that was easily prepared, yet nutritious and tasty. Today, donburi can be made with absolutely any topping, although it is usually prepared with various vegetables, eggs, meat (beef, pork, or chicken), soy, dashi, and mirin.