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.

bumping : Indicates that the affected part of the book has been impacted in such a way so as to cause a flattening, indention, or light bending.

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.