/ Dictionary / Index S sixty-fourmo: Meaning and Definition of Find definitions for: six•ty-four•mo Pronunciation: (siks"tē-fôr'mō, -fōr'-), [key] — n., pl. adj. -mos, —n. a book size (about 2 × 3 inches; 5 × 7 cm) determined by printing on sheets folded to form 64 leaves or 128 pages. a book of this size. Symbol: 64mo, 64° —adj. printed, folded, or bound in sixty-fourmo. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sixty-four-dollar question sixty-fourth Related Content Daily Word Quiz: winsome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language