octodecimo
/ˌɒktəʊˈdesɪməʊ/noun
(pl. -os)
1- a size of book page resulting from folding each printed sheet into eighteen leaves (36 pages)十八开本, 十八开。
1.1
- a book of this size十八开本的书。
词源
mid 19th cent.: from Latin in octodecimo 'in an eighteenth', from octodecimus 'eighteenth'.