octodecimo

 
Pronunciation: /ˌɒktəʊˈdɛsɪməʊ/

noun (plural octodecimos)

  • a size of book page resulting from folding each printed sheet into eighteen leaves (36 pages).
  • a book of octodecimo size.

Origin:

mid 19th century: from Latin in octodecimo 'in an eighteenth', from octodecimus 'eighteenth'