A reading day is a day set aside by a college, university or other school for study for final exams. It is scheduled after all the regular class lectures and before final exams. In many cases, student governments have lobbied to introduce, extend or preserve reading days as a day exclusively for study, and run into conflict with teachers who like to use it as an additional day for lectures or exams.
Another issue is that some students may prefer to take exams on reading day in order to get the semester over with. Some universities refer to a week of reading days as "dead week."