/ Dictionary / Index M mass psychology: Meaning and Definition of Find definitions for: mass' psychol'ogy Pronunciation: [key] the study of the behavior of large groups of people. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mass production mass society Related Content Daily Word Quiz: denizen Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language