That’s such an interesting question. I think of it as a place - the place where the shops are in your neighborhood. But then people use it to describe stores, like M&S and Toys R Us. But I don’t feel they use it to describe a store like Walmart, but maybe they do? That is, it’s a little more fashionable or more of a treat than that.
Back to say: I don’t think it’s the same as ‘down town’ personally, but maybe it is.