octodecimo
Rare / ObsoleteTechnical / Archaic
Definition
Meaning
A book size where each leaf is one eighteenth the size of the original printing sheet.
A book format; by extension, a book itself, particularly one of a small, specific size. Historically used in printing and bibliographic contexts.
Linguistics
Semantic Notes
The term refers specifically to the method of folding a sheet of paper to produce a certain number of leaves (pages). It is part of a series of Latin-derived book size names (folio, quarto, octavo, duodecimo).
Dialectal Variation
British vs American Usage
Differences
No significant usage difference; the term is equally archaic and technical in both regions.
Connotations
Connotes historical printing, bibliophilia, antiquarian book trade.
Frequency
Extremely rare in contemporary use, found only in specialist historical or bibliographic contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
[book/publication] is (in) octodecimoprinted/published/bound in octodecimoVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “none”
Usage
Context Usage
Business
Not used.
Academic
Used only in historical studies of printing, bibliography, or book history.
Everyday
Never used.
Technical
Precise term in descriptive bibliography for specifying book size based on sheet folding.
Examples
By Part of Speech
adjective
British English
- The library acquired an octodecimo edition of the poems.
American English
- It was a charming, octodecimo almanac from the 1820s.
Examples
By CEFR Level
- The old book was surprisingly small because it was printed in octodecimo.
- Bibliographers noted that the first edition appeared in octodecimo, making it a genuinely pocket-sized volume for its time.
Learning
Memory Aids
Mnemonic
Think of 'octo' (eight) and 'decimo' (tenth) – it's a confusing mix, but it results in 18 leaves from one sheet.
Conceptual Metaphor
BOOK SIZE IS A FOLDING PATTERN.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'octavo' (восьмушка) or 'duodecimo' (двенадцатая доля). 'Octodecimo' is a distinct, rarer size.
Common Mistakes
- Mispronouncing as 'octo-decimo' without the linking vowel /ə/ or /oʊ/.
- Confusing it with 'octavo' (8vo) or 'sextodecimo' (16mo).
Practice
Quiz
What does 'octodecimo' specifically refer to?
FAQ
Frequently Asked Questions
No, it is an archaic term from hand-press era printing. Modern printing uses metric or imperial dimensions (e.g., A5, 6x9").
The standard abbreviation is '18mo', derived from the Latin octo-deci-mo.
An octodecimo (18mo) book is smaller than an octavo (8vo) book, as more leaves are folded from the same sheet, resulting in smaller pages.
You should avoid it unless speaking to a specialist in historical books. It will not be understood by general audiences.