wraps : The paper covering on the outside of a paperback.

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.

cracked : In reference to a hinge or a book's binding, means that the glue which holds the opposing leaves has allowed them to separate, revealing the stitching or binding underneath.

8vo : Short for Octavo, A book whose page size is approximately 8-10 inches tall. The size is based on a sheet of paper 25 inches by 38 inches, the size of paper traditionally used by book printers, which has been folded and cut into 16 pages.. Unfortunately often misunderstood to mean 8 volumes.

hinge : The portion of a book near the spine that is intended to flex to allow the book to open.