Folio
FOH-lee-oh
A sheet of paper folded once to create two leaves (four pages); also used to describe large-format books made from such sheets, and as a general term for a single leaf in a manuscript or book.
Origin
From Latin "folium" (leaf). The term has been used in bookmaking since at least the 15th century.
In context
The Shakespeare First Folio of 1623 is the earliest collected edition of his plays — without it, half of them might have been lost.
The book was printed in folio — it was as large as a broadsheet newspaper and just as unwieldy.
The manuscript was numbered by folio: 'f. 12r' means folio 12, recto (right-hand page).
Did you know?
The Shakespeare First Folio (1623) — formally "Mr. William Shakespeares Comedies, Histories, & Tragedies" — contains 36 plays, 18 of which would not exist in any other source. Only about 235 copies survive. In 2020, one sold at Christie's for $9.98 million. The term "First Folio" has become a proper name; technically, Shakespeare's works were printed in a standard folio format.
A folio is a sheet of paper folded once, creating two leaves and four printable pages. From this simple operation comes one of the fundamental size categories of Western book history. In early printing, the size of a book was described by how many times the standard printing sheet had been folded: folio (once, for a large book), quarto (twice, for a medium book), octavo (three times, for a smaller book). The folio was the largest and most prestigious format, used for serious texts — Bibles, legal records, scientific treatises, collected literary works — that deserved the physical weight their content implied.
The relationship between folio format and cultural seriousness was real in the early print era. Printing a text in folio signaled that it was worth the expense: large paper, large type, broad margins for annotation. When John Heminge and Henry Condell, two of Shakespeare's fellow actors, compiled his plays into the First Folio in 1623 — seven years after the playwright's death — they were making a statement about Shakespeare's standing. Plays were not typically printed in folio, which was reserved for more elevated genres. The choice of format was an argument: these plays are literature, not disposable entertainment. History has agreed.
In manuscript studies, folio has a different but related meaning: a single leaf, numbered as folio 12 (abbreviated f. 12), with its two sides designated recto (the right, or front side, when the manuscript is read) and verso (the left, or back). Bibliographers and manuscript scholars use this system to cite locations precisely: "f. 14v" means folio 14, verso side. The system reflects the fact that medieval manuscripts were numbered by leaf rather than by page, a convention that persisted into early printed books.
Modern use of "folio" is most likely to appear in two contexts: the Folio Society, the British publisher known for its deluxe illustrated editions of classic texts, and the general meaning of "large format book." A coffee table book, an oversized art monograph, an atlas — these are sometimes described as "folio-sized" or simply as "folios" in the bookselling context, indicating they're too large for a standard shelf and typically stored lying flat. The format still carries some of its original implication: a folio book is a substantial object, made to be looked at as much as read.
Physical format affects how a book is read and where it lives. A folio-sized art book on a coffee table is a different kind of object from a pocket paperback — it invites a different posture, a different pace, a different relationship to the images and text it contains. The grandeur of large-format printing is one of the reasons fine press editions continue to be printed in folio-adjacent sizes: the physical experience of reading a large, well-made book is genuinely different from reading its octavo equivalent, and that difference is part of what the format communicates.