from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The page size, from 5 by 8 inches to 6 by 9 1/2 inches, of a book composed of printer's sheets folded into eight leaves.
  • n. A book composed of octavo pages.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A sheet of paper 7 to 10 inches high and 4.5 to 6 inches wide, the size varying with the large original sheet used to create it. Made by folding the original sheet three times to produce eight leaves.
  • n. A book of octavo pages.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Having eight leaves to a sheet
  • n. A book composed of sheets each of which is folded into eight leaves; hence, indicating more or less definitely a size of book so made; -- usually written 8vo or 8°.

from The Century Dictionary and Cyclopedia

  • Having eight leaves to a sheet; formed of sheets of paper so folded as to make eight leaves to the sheet: as, an octavo volume.
  • n. A book or pamphlet every section or gathering of which contains eight leaves, each leaf supposed to be one eighth of the sheet printed: usually written 8vo.
  • n. A sheet of paper evenly folded to make eight leaves and sixteen pages.
  • n. A form of type containing eight pages.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. the size of a book whose pages are made by folding a sheet of paper three times to form eight leaves


Medieval Latin (in) octāvō, (in) an eighth, from Latin, ablative sing. of octāvus, eighth, from octō, eight.
(American Heritage® Dictionary of the English Language, Fourth Edition)


  • A customer is likely to ask for Ivanhoe in English, octavo, bound in leather.

    The Classification of Patents

  • In the seventh edition (1720) I find to my great solace and comfort the entry, dog, 'a well-known creature, 'a somewhat meagre definition, improved into 'a quadruped well-known' by Nathaniel Bailey, whose dictionary, first published in octavo (1721), ran through a very large number of editions and became the standard authority until superseded by Johnson.

    On Dictionaries

  • XXXIX. of the third edition, in octavo; where it is likewise shown, that none of these parts which are deposited beneath the cuticle of the tree, is in itself

    Note I

  • Two professed Lives of Mahomet have been composed by Dr. Prideaux (Life of Mahomet, seventh edition, London, 1718, in octavo) and the count de Boulainvilliers, (Vie de Mahomed, Londres, 1730, in octavo:) but the adverse wish of finding an impostor or a hero, has too often corrupted the learning of the doctor and the ingenuity of the count.

    The History of the Decline and Fall of the Roman Empire

  • Poetry, (London, 1774, in octavo,) which was composed in the youth of that wonderful linguist.

    The History of the Decline and Fall of the Roman Empire

  • Of the various petitions, apologies, &c., published by the princes of Courtenay, I have seen the three following, all in octavo: 1.

    The History of the Decline and Fall of the Roman Empire

  • (Venezia, 1765, in octavo,) which represents the state and manners of Venice in the year 1008. 2.

    The History of the Decline and Fall of the Roman Empire

  • A book of this kind is not larger than a thin octavo, and it maybe easily carried by your maid in her reticule without any parade, as, if it should not be wanted, it will be of very little incumbrance; whereas, if you have a table and the apparatus for drawing carried out, and should not happen to be visited by the pictorial muse, you will find it very disagreeable to be joked on so formidable a preparation having produced no result.

    The Lady's Country Companion: or, How to Enjoy a Country Life Rationally

  • Philosophical Arrangements of Mr. James Harris, (London, 1775, in octavo,) who labored to revive the studies of Grecian literature and philosophy.] 60 Abulpharagius, Dynast.p. 81, 222.

    The History of the Decline and Fall of the Roman Empire

  • The xivth letter of Tournefort (Voyage du Levont, tom.ii. p. 325 — 360, in octavo) describes what he had seen of the religion of the Turks.] * Such is Mahometanism beyond the precincts of the Holy City.

    The History of the Decline and Fall of the Roman Empire


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  • Usually written as 8vo; the most common traditional book format, made from printed sheets folded three times, giving eight leaves (16 pages). Also used in a general way to indicate a book measuring about 7 x 10 inches.

    February 20, 2007