(Professionally Served Unadon/Unagi Donburi)
When you see the sign which says “XXX Don” or “OOO Donburi,” you picture “XXX Rice Bowl” or “OOO Bowl” you can eat at Japanese restaurants or Japanese/Chinese fast food restaurants like Panda Express. Originally, “donburi” means “medium sized bowls” – think of a salad bowl with quite a depth.
Usually, the Japanese serve rice in a deep bowl called donburi, over which you will see a lot of dishes – meat, eggs, fish, vegetables, and so on. Then, you call it “(whatever) Donburi.”
So, today’s “whatever” is eels called “Unagi” in Japanese. That’s why it is called “Unagi Donburi” or “Unadon” in a shortened form. Those eels are grilled like down below, seasoned and lightly boiled with sugar and soy sauce, and served over rice (Yum!). Since Japanese eels are considered to be very nutritious and to give you full energy, Unagi Donburi tends to be served especially in summer, when people easily get tired because of the heat.