What does quarto mean?
Quarto is a book-format term for a sheet of paper folded twice, creating four leaves, or eight pages, in the finished book. It can describe either the physical process or a book produced in that format, as in “printed in quarto” or “a quarto edition.” The term is especially associated with bibliographies, library catalogues, and descriptions of historical books, where a publication’s format and approximate size may be recorded together. Quarto belongs to a family of book formats named according to the number of leaves formed from a sheet: a folio is folded once, a quarto twice, and an octavo three times. Although quarto no longer specifies a single standardized physical size, it remains a precise and useful term. Its vocabulary value lies in preserving a traditional method of describing how printed sheets are folded, while also providing modern readers with a concise way to discuss the appearance and construction of books.
A book printed on sheets folded twice, each sheet forming four leaves or eight pages; also, a publication in this historical format.
"The rare quarto was bound in full calf."
Common in bibliographical descriptions and catalogues, particularly for early printed books.
Consisting of sheets folded twice into four leaves, or eight pages.
"The publisher issued a quarto edition with generous margins."
Usually appears attributively, especially in the expression “quarto edition.”
The plural is used when referring to multiple books or editions in quarto format.
"The collection includes several early quartos of classical works."
A folio folds once, a quarto twice: the name preserves the fact that each sheet ultimately produces four leaves.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does quarto come from?
The word entered English from Italian quarto, meaning “fourth,” in the early 16th century. Italian borrowed the term from Latin quartus, the ordinal meaning “fourth,” which derives from quattuor, “four.” The format was named because each folded sheet produced four leaves, and the Latin root also underlies English words such as “quarter,” “quartet,” and “quaternary.”
How quarto is actually used
Chiefly a bibliographical and publishing term, especially common in catalogues and descriptions of early printed books. It is more technical than the everyday word “book” but less specialized than terms used for individual sheet sizes.
Easily confused with quarto
A folio sheet is folded once to form two leaves or four pages, whereas a quarto sheet is folded twice to form four leaves or eight pages.
An octavo is folded three times to form eight leaves or sixteen pages, while a quarto is folded twice.