/ Dictionary / Index P protostele: Meaning and Definition of Find definitions for: pro•to•stele Pronunciation: (prō'tu-stēl", -stē"lē), [key] — n. Bot. the solid stele of most roots, having a central core of xylem enclosed by phloem. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. protostar protostome Related Content Daily Word Quiz: penurious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language