Meaning of 东西

[Lafaso870]

"东西".. Since RS gives no definitions, I went with my gut on the meaning, and apparently was totally wrong according to any dictionary I've checked.

The only sentence they give with this word is:
这只狗在吃东西。
It shows a picture of a dog eating dog food. Since at this point we've been given several items of food, I assumed it meant "dog food"...

However, the dictionary disagrees (rightfully I'm sure)...
It looks like in that context, it simply means "something", right?

The most basic translation of 东西 ([dōngxī]) is "east and west"...
Other definitions include:
1. thing; stuff
2. (referring to an animal) thing; creature
3. noun [Offensive] (refering to a person) thing, used as an insult

So... was this RS's cute way of avoiding teaching the word for dog food by simply saying the dog is eating... something?

And, more importantly, is this a word one would use regularly if you're referring to "stuff"?