wrappers : Paperback or softbound. Also, wraps.

leaves : When used to refer to a part of a book means the book's pages.

recto : The page on the right side of a book, with the term Verso used to describe the page on the left side.

quarto : A term used generally to describe the approximate size of a book, a book that is about 10" to 12" tall and roughly squarish in shape. The term is based on the size of paper traditionally used by book printers which has been folded and cut into 16 pages.