Longman Dictionary English From Longman Dictionary of Contemporary EnglishRelated topics: Linguisticsarchaismar‧cha‧is‧m /ˈɑːkeɪ-ɪzəm, ɑːˈkeɪ- $ ˈɑːrki-/ noun [countable] SLan old word or phrase that is no longer used ldoceonline.com