/ Dictionary / Index M macroorganism: Meaning and Definition of Find definitions for: mac•ro•or•gan•ism Pronunciation: (mak"rō-ôr'gu-niz"um), [key] — n. an organism that can be seen with the naked eye. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. macronutrient macrophage Related Content Daily Word Quiz: ontiguous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language