/ Dictionary / Index P prop root: Meaning and Definition of Find definitions for: prop' root" Pronunciation: [key] — Bot. Bot. an adventitious root that supports the plant, as the aerial roots of the mangrove tree or of corn. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. proprio motu* propter hoc* Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language