/ Dictionary / Index H heart block: Meaning and Definition of Find definitions for: heart' block" Pronunciation: [key] — Pathol. Pathol. a defect in the electrical impulses of the heart resulting in any of various arrhythmias or irregularities in the heartbeat. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. heartbeat heartbreak Related Content Daily Word Quiz: reclusive Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language