/ Dictionary / Index R reduction division: Meaning and Definition of Find definitions for: reduc'tion divi"sion Pronunciation: [key] — Biol. Biol. the first division of meiosis in which the number of chromosomes is reduced to half the original number. meiosis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. reduction reductionism Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language