From Longman Dictionary of Contemporary Englishjackhammerjack‧ham‧mer /ˈdʒækˌhæmə $ -ər/ noun [countable] 
American EnglishTZTBC a large powerful tool used to break hard materials such as the surface of a road SYN pneumatic drill British English
American EnglishTZTBC a large powerful tool used to break hard materials such as the surface of a road SYN pneumatic drill British EnglishExamples from the Corpus
jackhammer• My responsibility button was being hit with the force of a jackhammer.• A jackhammer started up somewhere beyond the prison walls.• But today, crews wielding jackhammers are frantically repairing the narrow streets. 