Collegiate describes anything to do with college life or college students. You might refer to the leagues in which college athletes compete as collegiate sports, or to students studying chemistry as collegiate scientists.
While college is a noun, collegiate is an adjective used to describe anything associated with college. The word collegiate was once associated with the idea of ivy-covered walls and impeccably-dressed students earnestly discussing philosophy and art. Nowadays, it can just as easily refer to political demonstrations and raucous behavior, as all have become part of the collegiate world.