/ Dictionary / Index R root hair: Meaning and Definition of Find definitions for: root' hair" Pronunciation: [key] an elongated tubular extension of an epidermal cell of a root, serving to absorb water and minerals from the soil. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. root graft rooti Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language