What is the difference between "meshi" and "don" for the food sometimes translated as "rice bowl" in English?

Question

I'm a big fan of the Japanese fast food gyudon (cooked thinly sliced beef strips on top of a bowl of boiled white rice) and its variants such as butadon (the same but with pork).

But why do some chain restaurants call it "gyudon" and others "gyumeshi"? Are both spelled the same?

Also at my local Japanese restaurant at home in Australia they seem to sell this dish but never understand me when I ask for gyudon. Does it have other names or are there simply dishes which seem alike to ignorant foreigners like me?

Answer 1

The 丼 donburi in 牛丼 gyūdon specifically denotes a bowl of rice.
The 飯 meshi in 牛飯 gyūmeshi just means rice or even more generically meal.

Both describe the same thing:

ぎゅう‐どん【牛丼】
「牛飯（ぎゅうめし）」に同じ。

"See gyūmeshi."

ぎゅう‐めし【牛飯】
ネギなどと煮た牛肉を、汁とともにかけたどんぶり飯。牛丼（ぎゅうどん）。

"A rice meal with onions and fried beef [...]. Gyūdon."

I'm not sure which one is preferred in which situation, but personally I see more gyūdon in daily life (caveat: I don't eat it too often though). There are many specialized kinds of 丼 donburi, while 飯 meshi can be used for almost anything edible and is usually just used in the sense of "meal". It can also specifically denote rice though, as in 焼飯 yakimeshi - "fried rice", which is more often called チャーハン chāhan though.