In my head, I tend to base Stanford's campus on that of Duke University, even though it's on the opposite side of the country, just because I visited it a couple of times and it's on the same "level" as Stanford. On their campus, there is a difference between a dorm and a house. A dorm is a larger building (the one my friend lived in as a freshman had previously been a hospital) where basically random students live. A house is a smaller building where people choose to live based on an interest. My friend's house was like a stone row-home in the middle of a line of other student houses. And yeah, they're on campus.

On the other hand, many fraternity houses (not sure about Duke in particular but at other schools) are off-campus but very close to campus.