/ Dictionary / Index M modular arithmetic: Meaning and Definition of Find definitions for: mod'ular arith'metic Pronunciation: [key] arithmetic in which numbers that are congruent modulo a given number are treated as the same. Cf.(def. 2),(def. 2b). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. modular modularity Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language