At Cambridge, as well as being a member of the University, you'll also be a member of a College.
Your College is much more than a hall of residence; it's also where you'll do a lot of your studying and socialising. How much time you spend in your College is up to you. For some students, their College is simply the place where they sleep and attend supervisions. For most, though, it provides experiences and friendships that can last a lifetime.