Archaea

ar;chaea pronunciation: function: noun plural etymology: new latin, from greek archaiosdate: 1990 : microorganisms of a domain (archaea) including especially methane-producing forms, some red halophilic forms, and others of harsh hot acidic environments (as a hot spring) — compare bacterium, eukaryote— ar;chae;al adjective — ar;chae;an adjective or noun