I think there is a split of usage as to whether "hash browns" refer to patties or to loose potato chunks. And now that I am confronted with this split, I don't know which side I come down on, because 99% of the time my breakfasts consist of toast or bagels.

But I suppose rosti is not unlike a patty-style hash brown, really, though a bit less greasy in my mind and with optional (but yummy) cheese. And a lot bigger. And dinner not breakfast. =>