folio

Etymology

It is inherited from Middle English folio,^[2][3] borrowed from Late Latin foliō (“leaf or sheet of paper”),^[4][5][3] the ablative of folium (“leaf”),^[6][4][5][2] used in medieval Latin page references to mean "at leaf so-and-so".^[7][8][9][4] The phrase in folio, for a sheet folded once, is either Latin or a refashioning of Italian in foglio,^[6][7][4] and the bookkeeping sense may also come from foglio.^[6][10] The Latin word, the source also of French feuille and Spanish hoja,^[5] goes back to Proto-Indo-European *bhol-yo- (“leaf”), a suffixed form of *bhel- (“to thrive, bloom”),^[5][3] and is cognate with Ancient Greek φύλλον (phúllon, “leaf”) and Scottish Gaelic bile (“leaflet, blossom”).^[5][11]

Earliest recorded meaning

A leaf of a book: 1447, in the accounts of St Mary's, Thame, which list books by the words that begin their second folio.^[2][4] The OED's first record of the English word is from 1533, in More, for a leaf numbered only on the front.^[6]

Semantic evolution

The first sense came from page references, where the ablative folio meant "on the leaf".^[6][8][9] From 1588 it was used in bookkeeping for the two facing pages of a ledger,^[6] later also for the page number of a printed book.^[6] The phrase in folio, a full-sized sheet folded once, is recorded from 1582;^[6][4] from it came the senses of a sheet folded once (1616) and of a book made of such sheets, the largest common size of book (1628 in the OED, the 1620s in Etymonline).^[6][5][9] Johnson (1755) defined it as a large book whose pages are formed by a sheet once doubled.^[12] The adjective, of folio size, is recorded from 1597.^[6] In law, from 1836, a folio is a fixed number of words used to measure the length of a document: 72 or 90 in Britain and 100 in the United States.^[6][13] The verb, to number the leaves or pages of a book, dates from 1858.^[14] In Yorkshire dialect in full folio meant in full dress or grand style.^[15]

Timeline

• 1447 – a leaf of a book or manuscript.^[2][4] The OED dates it to 1533.^[6]
• 1582 – in folio, in the form of a sheet folded once.^[6][4]
• 1588 – in bookkeeping, two facing pages of a ledger.^[6]
• 1597 – adjective, made of sheets folded once; of the largest size.^[6]
• 1616 – a sheet of paper folded once.^[6]
• 1628 – a volume made of such sheets; a book of the largest size.^[6] Etymonline dates it to the 1620s.^[5]
• 1683 – the page number of a printed book.^[6]
• 1836 – in law, a unit of a fixed number of words in a document.^[6]
• 1858 – verb, to number the leaves or pages of a book.^[14]

Meanings

Noun

1. A leaf of a manuscript or book, especially one numbered only on the front.^[13][14][6]
2. A sheet of paper folded once to make two leaves, or four pages, of a book.^[13][6]
3. A book or manuscript made of such sheets; a volume of the largest common size: The library keeps its rare folios in a separate room.^[13][14][6]
4. A page number in a book.^[13][14][6]
5. In bookkeeping, two facing pages of a ledger used together.^[6][14]
6. (law) A unit for measuring the length of a legal document, a fixed number of words, generally 72 or 90 in Britain and 100 in the United States.^[13][6]
7. (New Zealand) A collection of related material.^[13]

Adjective

1. Made of sheets folded once; of the size of a folio: a folio edition of the plays.^[13][14][6]

Verb

1. To number the leaves or pages of a manuscript or book.^[14]

Related words

• foliage
• foliate
• foil
• portfolio
• quarto
• octavo
• blade
• bloom

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
3. ^ a b c The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
4. ^ a b c d e f g h Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
7. ^ a b Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
8. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
9. ^ a b c Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
10. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
11. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
12. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
13. ^ a b c d e f g h Collins English Dictionary (2023), Glasgow: HarperCollins
14. ^ a b c d e f g h Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
15. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)