twenty-fourmo

[twen-tee-fawr-moh, -fohr-, twuhn-]

noun, plural twen·ty-four·mos.

a book size of about 3 5/8 × 5 1/8 inches (9 × 13 cm), determined by printing on sheets folded to form 24 leaves or 48 pages.
a book of this size. Symbol: 24mo, 24°

adjective

in twenty-fourmo.

Origin of twenty-fourmo

First recorded in 1835–45; twenty-four + -mo
Also called vigesimoquarto.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019