- a book size of about 4 × 6 1/4 inches (10 × 16 cm), determined by printing on sheets folded to form 18 leaves or 36 pages. Symbol: 18mo, 18°
- a book of this size.
- in octodecimo.
Origin of octodecimo
1855–60; short for New Latin in octōdecimō in an eighteenth (of a sheet)
Also called eighteenmo.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for octodecimo
Other sizes occasionally used are called “sixteenmo” or “sextodecimo,” “eighteenmo” or “octodecimo,” etc.The Story of Books
Gertrude Burford Rawlings
- bookbinding another word for eighteenmo
C18: from New Latin phrase in octodecimo in an eighteenth (of a whole sheet)