• WordNet 3.6
    • n octavo the size of a book whose pages are made by folding a sheet of paper three times to form eight leaves
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Webster's Revised Unabridged Dictionary
    • n Octavo 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°.
    • a Octavo Having eight leaves to a sheet; as, an octavo form, book, leaf, size, etc.
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Century Dictionary and Cyclopedia
    • octavo 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 octavo 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. When the name of the paper of which the book is made is not specified, an octavo is understood as a medium octavo, 6 × 9½ inches. Smaller octavos are — post 8vo, 5½ × 8½ inches; demy 8vo, 5¼ × 8 inches; crown 8vo, 5 × 7½ inches; cap 8vo, 4¼, × 7 inches. Larger octavos are — royal 8vo, 6½ × 10 inches; superroyal 8vo, 7 × 11 inches; imperial 8vo, 8¼ × 11½ inches. These are regular octavo folds of established sizes of paper in the United States. Publishers and booksellers describe as octavos only those books or leaves that are larger than 5½ × 8 and smaller than 7½ × 11½ inches, irrespective of the number of leaves in a section, which may be twelve or sixteen on thin paper and four or six on thick paper. Larger sizes are described as 4to, smaller sizes as 12mo or 16mo. Bibliographers, as a rule, limit the use of the word octavo to books having sections of eight leaves or sixteen pages.
    • n octavo A sheet of paper evenly folded to make eight leaves and sixteen pages.
    • n octavo A form of type containing eight pages.
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Chambers's Twentieth Century Dictionary
    • adj Octavo ok-tā′vō having eight leaves to the sheet
    • n Octavo a book printed on sheets folded into eight leaves, contracted 8vo—usually meaning a medium octavo, 6×9½ inches. Smaller octavos are—post 8vo, 5½×8½ in.; demy 8vo, 5¼×8 in.; crown 8vo, 5×7½ in.; cap 8vo, 4½×7 in. Larger octavos are—royal 8vo, 6½×10 in.; super-royal 8vo, 7×11 in.; imperial 8vo, 8¼×11 in.:—pl. Octā′vos
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Webster's Revised Unabridged Dictionary
L. in octavo,; in, in + octavo, abl. of octavus,. See Octave


In literature:

Set these rolls on end on the table, and they will carry the small octavo perfectly well.
"The Stones of Venice, Volume I (of 3)" by John Ruskin
The whole will be comprised, probably, in six octavo volumes.
"Harper's New Monthly Magazine, Volume 2, No. 12, May, 1851." by Various
The first volume was issued in May, 1881, a royal octavo of 900 pages, bringing the record down to the beginning of the Civil War.
"The Life and Work of Susan B. Anthony (Volume 2 of 2)" by Ida Husted Harper
Probably the octavo edition of 1711.
"Hazlitt on English Literature" by Jacob Zeitlin
It would make a supplement to the 'Biographia Literaria,' in a volume and a half, octavo.
"Old and New London" by Walter Thornbury
Judging from these fly-leaves, the work from which they have been taken appears to have been an octavo or small quarto.
"Notes and Queries, Number 239, May 27, 1854" by Various
Its shape is a slender, tall octavo.
"The Works of Robert Louis Stevenson - Swanston Edition Vol. 24 (of 25)" by Robert Louis Stevenson
This extends over sixty-nine octavo pages.
"Etna" by G. F. Rodwell
The latter alone covers two large octavo pages of small print.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 7" by Various
One volume, square octavo.
"Eureka:" by Edgar A. Poe

In poetry:

Physics, metaphysics, logic, mathematics--all the lot
Every wisdom--crammed octavo he has mastered and forgot,
With the ghosts of dead professors standing guard beside them all;
And the room is fall of shadows which their lettered backs recall.
"The Last Survivor" by Oliver Wendell Holmes

In news:

Octavo Singers and Oratorio Society kick off season at same time.
Political and social intrigue are merged through the medium of the mystical card layout called the Octavo in this debut novel of maneuvering aristocrats and striving tradesmen in late 18th-century Stockholm.
"The Stockholm Octavo " is the title of Karen Engelmann's sparkling new debut hardcover novel set for release tomorrow (Tuesday).
Octavo Singers and Oratorio Society kick off season at same time.
The Stockholm Octavo,' by Karen Engelmann.
Karen Engelmann's 'The Stockholm Octavo,' reviewed by Ron Charles.
Karen Engelmann on her debut novel, The Stockholm Octavo.
"The Stockholm Octavo," by Karen Engelmann.
Jeff Glor talks to Karen Engelmann about, "The Stockholm Octavo.".
The Stockholm Octavo was in many respects inspired by the city itself.