[weiming]

[CAUTION: I am not a teacher:take the advice and or corrections offered in this post at your own risk.
If you doubt the information, please get a qualified opinion from one of the teachers on these forums.]

I'm not 100% sure on these, but my posts tend to be scrutinised, so you should have a definite answer in no time.

A university seems to offer higher degrees and be more accredited than a college.

I think any institution offering undergraduate degrees like a Bachelor's degree or even an Associate's (2 year) degree can be a college.

A university (I think) must offer post graduate degrees, doctorates and the like.

Also I'm sure there's some specific difference in the way they're accreddited and administered, but I haven't the foggiest of what that difference might be. It's like asking when a rock stops being a rock and becomes a boulder.

A hallway can be just a hall, like at the entrance to a building, a hallway may have one opening at each end and no others. It seems hallways tend to be larger than corridors.

A corridor has been defined as a narrow hallway or passageway, usually with rooms opening onto it. I would not call the spaces between rooms on a ship a "hallway". But then I would not call the spaces between classrooms in a school a "corridor", probably because they tend to be large, though I don't see why one couldn't.

If you're not sure and you're in a building, use the word "hallway". If you're on ship or train with a passageway connecting rooms, you might say "corridor".