/ Dictionary / Index P primary root: Meaning and Definition of Find definitions for: pri'mary root' Pronunciation: [key] — Bot. Bot. the first root produced by a germinating seed, developing from the radicle of the embryo. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. primary rainbow primary school Related Content Daily Word Quiz: winsome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language