/ Dictionary / Index M mosaicism: Meaning and Definition of Find definitions for: mo•sa•i•cism Pronunciation: (mō-zā'u-siz"um), [key] — n. Biol. a condition in which an organism or part is composed of two or more genetically distinct tissues owing to experimental manipulation or to faulty distribution of genetic material during mitosis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mosaicism (Thesaurus) mosaic gold mosaicist Related Content Daily Word Quiz: digression Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language