OCTODECIMO
Etymology
Noun
octodecimo (plural octodecimos)
(paper, printing) A size of a sheet of paper resulting from folding and cutting a sheet of paper into eighteenths (3.5"-4.5" x 4.9"-5.9").
(printing) A book consisting of pages of that size.
Synonyms
• (paper size): 18mo, eighteenmo, 18º
• (book size): 18mo, eighteenmo, 18º, T
Source: Wiktionary
Oc`todec"i*mo, a. Etym: [L. octodecim eighteen. See Octavo, Decimal,
and -mo.]
Definition: Having eighteen leaves to a sheet; as, an octodecimo form,
book, leaf, size, etc.
Oc`to*dec"i*mo, n.; pl. Octodecimos (.
Definition: A book composed of sheets each of which is folded into eighteen
leaves; hence; indicating more or less definitely a size of book,
whose sheets are so folded; -- usually written 18mo or 18º, and
called eighteenmo.
Source: Webster’s Unabridged Dictionary 1913 Edition