Breadcrumb Home > Dictionary > Index J Cite jackhammer: Meaning and Definition of Find definitions for: jack•ham•mer Pronunciation: ( jak'ham"ur), [key] — n. a portable drill operated by compressed air and used to drill rock, break up pavement, etc. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: jackhammer (Thesaurus) jackfruit Jackie TrendingHere are the facts and trivia that people are buzzing about. January 2021 Current Events: US News Noble Titles and Ranks in a Monarchy Chinese New Year History, Meaning, and Celebrations The Manchu Keeping Your Brain Active in a COVID-19 World Inaugural Trivia Related Content Daily Word Quiz: evanescent Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language