is a book approximately 7 by 4.5 inches in size, or similar in size to a contemporary mass market paperback
. Also called a twelvemo, duodecimo
comes from Latin, and refers to the practice of taking a standard printing sheet from a printing press, and folding and refolding it until the pages are at the desired size. More familiar terms include folio
, which (at least originally), referred to pages folded in half, or quarters, respectively. Once the folds were made, the outside edges are trimmed before binding. An octavo
, one eighth the size of a standard printed sheet used by book printers is about the size of a contemporary hardback book or trade paperback
A duodecimo page is one twelfth the size of the original printed paper, and on a standard modern printing generally ends up close to 7 inches in height and about 4 1/2 inches wide after trimming. This is an example of a duodecimo sized printing and binding:
Strictly, the term refers to the number of folds made to a paper after printing and before being bound into a book, and therefore the size can vary. The pages of any duodecimo volume will be printed on twelve leaves
(24 pages). A standard printed sheet is 25 inches by 38 inches traditionally, and octavo
have become standard sizes for books based on this measurement.
Synonyms and abbreviations for duodecimo include: D, 12º, twelvemo, and 12mo.