/ Dictionary / Index P plasmosome: Meaning and Definition of Find definitions for: plas•mo•some Pronunciation: (plaz'mu-sōm"), [key] — n. Cell Biol. a true nucleolus, as distinguished from a karyosome. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. plasmolysis Plassey Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language