Meaning of twenty-fourmo

twen•ty-four•mo

Pronunciation: (twen"tē-fôr'mō, -fōr'-, twun'-), [key]
— n., pl. adj. -mos,
—n.
  1. a book size of about 3 × 5 in. (9 × 13 cm), determined by printing on sheets folded to form 24 leaves or 48 pages.
  2. a book of this size. Symbol: 24mo, 24°
—adj.
  1. in twenty-fourmo. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.