circulating material is material that can be borrowed from the library.
This means that an item may be checked out. Not all Library items circulate: Reference books, for example, must be used in the Library.
items that can be borrowed from the library are said to circulate. Some materials, such as those in Reference, are non-circulating.
a book or other material that may be borrowed from the library for a certain amount of time. Reference books and periodicals do not circulate. They are available for use only in the Library.
When we say a book or video or CD "circulates" or is in the "circulating" collection, all it means is that that book, unlike a " reference" book, can be checked out and used outside the library. Reference books are for use inside the library only.