DJ : Short for dust jacket, a protective and often decorative wrapper, usually made of paper which wraps around the binding of a book.

spine : The outer portion of a book which covers the actual binding. The spine usually faces outward when a book is placed on a shelf. Also known as the back.

Brodart : Generally used to refer to a clear plastic cover that is sometimes added to the dustjacket or outside covering of a book. The name refers to the company by the same name which produces many book repair and archival products.