[ ok-tey-voh, -tah- ]
/ ɒkˈteɪ voʊ, -ˈtɑ- /

noun, plural oc·ta·vos for 2.

a book size of about 6 × 9 inches (16 × 23 cm), determined by printing on sheets folded to form 8 leaves or 16 pages. Symbol: 8vo, 8°
a book of this size.


in octavo.

Origin of octavo

1575–85; short for New Latin in octāvō in an eighth (of a sheet)
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for octavo

British Dictionary definitions for octavo


/ (ɒkˈteɪvəʊ) /

noun plural -vos

Also called: eightvo a book size resulting from folding a sheet of paper of a specified size to form eight leavesdemi-octavo Often written: 8vo,
a book of this size
(formerly) a size of cut paper 8 inches by 5 inches (20.3 cm by 12.7 cm)

Word Origin for octavo

C16: from New Latin phrase in octavo in an eighth (of a whole sheet)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for octavo



1580s, printer's word for sheets folded to make eight leaves, from Latin in octavo "in the eighth," ablative of octavus "eighth" (see octave). Abbreviation is 8vo.

Online Etymology Dictionary, © 2010 Douglas Harper