WordReference Random House Unabridged Dictionary of American English © 2026
twen•ty-four•mo
(twen′tē fôr′mō, -fōr′-, twun′-),USA pronunciation n., pl. -mos, adj.
n.
adj.
n.
- Printinga book size of about 35⁄8 × 51⁄8 in. (9 × 13 cm), determined by printing on sheets folded to form 24 leaves or 48 pages.
- Printinga book of this size. Symbol: 24mo, 24°
adj.
- Printingin twenty-fourmo. Also called vigesimoquarto.
- twenty-four + -mo 1835–45
'twenty-fourmo' also found in these entries (note: many are not synonyms or translations):