When I search for a book, it says 'Central Reserves' as location. What does that mean?

A location of Central Reserves means that the book has been placed on reserve to be used as a course reading. Materials listed as in Central Reserves are held at the service desk on the fourth floor (main level) of Central Library. These materials typically have a short loan period (such as 2-3 hours at a time) in order to maximize the number of students able to access the material. If you check out any of these materials, you are responsible for returning them within the specified number of hours.