/ Dictionary / Index R rhizo-: Meaning and Definition of Find definitions for: rhizo- Pronunciation: [key] a combining form meaning “root,” used in the formation of compound words: rhizophagous. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. -rhiza rhizobium Related Content Daily Word Quiz: overture Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language