close down UK /kləʊzˈdaʊn/US /kloʊzˈdaʊn/ verb2 •To stop trading as a business.The local factory will close down soon, unless sales pick up.They had to close the mine down as it was in a dangerous condition. •To surround someone, as to impede their movement.If anyone passes to Smith, close him down. formsclosed down · closing down · closes down