Quarto (noun)

1. A book size, typically 9 x 12 inches (23 x 30 cm), or a book of this size.
2. A sheet of paper folded twice to form four leaves or eight pages.

Origin:

From the latin word quartus, meaning "fourth".

Examples:

1. The manuscript was written on quarto pages.
2. The publisher released the new novel in quarto format.
3. The rare book collection included a first edition quarto of Shakespeare's plays.
4. The printer had to adjust the press to accommodate the larger quarto size.
5. The artist used a quarto sketchbook for her preliminary drawings.