/ Dictionary / Index F fault block: Meaning and Definition of Find definitions for: fault' block" Pronunciation: [key] — Geol. Geol. a mass of rock bounded on at least two opposite sides by faults. Cf. block faulting. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. fault fault breccia Related Content Daily Word Quiz: morose Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language