octodecimo noun.
[ɒktǝʊ'dɛsɪmǝʊ] Pl.
-os.
M19.[Latin (in) octodecimo in an eighteenth (sc. of a sheet), from octodecimus eighteenth.]A size of book or paper in which each leaf is one-eighteenth of a standard printing-sheet. Also, a book or page of this size.
[TahlilGaran] English Dictionary ▲