What is the Full Form of CERN ?

CERN - Conseil Européen pour la Recherche Nucléaire (in French)       
           European Council for Nuclear Research (in English)

European Council for Nuclear Research is an International Organization of European states established on 29 September 1954, Headquartered in Geneva, Switzerland. The organization has now been renamed to European Organization for Nuclear Research (Organisation Européenne pour la Recherche Nucléaire, in French)

At the time of establishment, the sole purpose of this organization was to provide a place for world-class fundamental physics research.