a solemn assembly in the Roman Catholic Church, convoked and presided over by the pope and composed of cardinals, bishops, and certain other prelates whose decrees, when confirmed by the pope, become binding.
British Dictionary definitions for ecumenical council
ecumenical council
noun
an assembly of bishops and other ecclesiastics representative of the Christian Church throughout the world. Roman Catholic canon law states that an ecumenical council must be convened by the pope
