octodecimo

enUK

oc·to·dec·i·mo

O0028000 (ŏk′tə-dĕs′ə-mō′)n. pl. oc·to·dec·i·mos 1. The page size, 4 by 6.5 inches, of a book composed of printer's sheets folded into 18 leaves or 36 pages.2. A book composed of octodecimo pages. In both senses also called eighteenmo.
[Late Latin (in) octōdecimō, (in) an eighteenth, ablative sing. of octōdecimus, eighteenth, from Latin octōdecim, eighteen : octō, eight; see oktō(u) in Indo-European roots + decem, ten; see dekm̥ in Indo-European roots.]

octodecimo

(ˌɒktəʊˈdɛsɪməʊ) n, pl -mos (Printing, Lithography & Bookbinding) bookbinding another word for eighteenmo[C18: from New Latin phrase in octodecimo in an eighteenth (of a whole sheet)]