Word.ws English Dictionary

12mo

12mo noun: a book size using duodecimo-sized pages. Also the abbreviation of duodecimo.

Noun

12mo (usually uncountable, plural 12mos)

  1. (usually) A book size using duodecimo-sized pages.
    Synonyms:
    D, 12º, twelvemo, duodecimo

Also used as

12mo is also the abbreviation of duodecimo.

Synonyms of 12mo

Forms of 12mo

plural12mos

Origin of 12mo

12 + -mo, for a twelfth of a sheet.

Questions about 12mo

What does 12mo mean?
12mo means a book size using duodecimo-sized pages.
What part of speech is 12mo?
12mo is a noun.
What is the plural of 12mo?
The plural of 12mo is 12mos.

Words near 12mo in the dictionary

  1. 1260s
  2. 128th note
  3. 128th notes
  4. 12D chess
  5. 12ga
  6. 12mo
  7. 12mos
  8. 12s
  9. 12th
  10. 12th grade
  11. 12th grader

Source and license

Adapted from Wiktionary: 12mo (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Cite this entry: “12mo.” Word.ws, https://word.ws/12mo. Based on Wiktionary, CC BY-SA 4.0.