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.

tight : Used to mean that the binding of a book has not been overly loosened by frequent use.

crisp : A term often used to indicate a book's new-like condition. Indicates that the hinges are not loosened. A book described as crisp will not have 'well-read' pages, i.e., where the book will naturally open to certain pages or sections.