demy

 
Pronunciation: /dɪˈmʌɪ/
(also metric demy)

noun

[mass noun]
  • a paper size, 564 × 444 mm.
  • (also demy octavo) a book size, 216 × 138 mm.
  • (also demy quarto) a book size, 276 × 219 mm.

Origin:

late Middle English (as an adjective in the sense 'half-sized'): from demi-, or from its source, French demi 'half'