folium

Folio comes from Latin folium, meaning 'leaf' — a leaf of a plant, and by extension, a leaf of a book. The connection between botanical leaves and book leaves is ancient and deliberate: both are thin, flat, two-sided surfaces, and the words for them are cognate or identical across many languages. Greek φύλλον (phyllon), Latin folium, English 'leaf' and 'folio' — all name the same shape in different contexts. Latin folium entered book terminology in the sense of a single leaf of parchment or papyrus, which had two surfaces (sides): the recto (right side, front) and the verso (turned side, back). A folio in the technical sense of book production is a sheet of paper folded once to create two leaves and four pages — the largest standard book format, producing pages roughly 38 by 30 centimeters.

The folio format is most famous in English literary culture for its association with Shakespeare. The First Folio of 1623 — formally titled Mr. William Shakespeares Comedies, Histories, & Tragedies — was the first collected edition of Shakespeare's plays, published seven years after his death by his fellow actors John Heminges and Henry Condell. Of Shakespeare's thirty-seven plays, eighteen had never been printed before the First Folio; had it not been published, those plays would almost certainly be lost. The physical format of the Folio — large, substantial, expensive — was chosen to signal the dignity of its contents: plays printed as literature rather than as working scripts. Only 235 copies of the First Folio survive, of which approximately 82 are complete. Each is worth many millions of dollars. The leaf that saved half of Shakespeare's work is itself now one of the most valuable objects in the English-speaking world.

The word folio appears in publishing in several distinct senses that are easy to confuse. A folio can be: a leaf of manuscript or printed book; a sheet folded to make two leaves (the book format); a page number (from the Latin practice of numbering leaves rather than pages — both sides of a leaf shared one folio number); or a large-format book in general. The confusion of these senses is productive: all of them trace back to the same Latin leaf, just seen from different angles — the leaf as physical surface, the leaf as folded sheet, the leaf as numbered location, the leaf as format category. The botanical origin holds all of these together.

The modern use of 'portfolio' derives directly from folio: it is a carrying case (from Latin portare, to carry) for folios — originally a folder for holding loose papers and drawings, now metaphorically a collection of an artist's, investor's, or professional's work. The portfolio carries your leaves. Digital portfolios extend the metaphor further: the leaves have no physical existence, but the organizing concept of a collected, curated selection of one's work persists from the Latin leaf through the leather folder to the website. The plant world keeps finding its way into the vocabulary of writing.