/ Dictionary / Index M mass noun: Meaning and Definition of Find definitions for: mass' noun" Pronunciation: [key] a noun, as water, electricity, or happiness, that typically refers to an indefinitely divisible substance or an abstract notion, and that in English cannot be used, in such a sense, with the indefinite article or in the plural. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mass movement mass number Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language