/ Dictionary / Index M Microciona*: Meaning and Definition of Find definitions for: Mi•cro•ci•on•a Pronunciation: (mī"kru-sī'u-nu), [key] — n. a genus of bright-red sponges of the Atlantic coasts of North America and Europe, used in experiments on the dissociation and reintegration of sponge cells. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. microchip microcircuit Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language