Shelf mark is a term used to describe a label or notation that identifies the location of a book or other material on a library shelf. There are several synonyms for this term, including call number, classification number, book label, book number, and location marker. These terms are essential for librarians and library users to locate and retrieve materials quickly and efficiently. The shelf mark is typically composed of a combination of letters and numbers, representing the classification system used by the library. While the term shelf mark may not be familiar to everyone, the importance of these labels is undeniable in the organization and management of library collections.