/ Dictionary / Index R rift zone: Meaning and Definition of Find definitions for: rift' zone" Pronunciation: [key] — Geol. Geol. a system of related, narrow structural depressions between parallel faults. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Rift Valley fever rig Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language