From Longman Dictionary of Contemporary Englishcooling towerˈcooling ˌtower noun [countable] 
TPa large round tall building, used in industry for making water cool
TPa large round tall building, used in industry for making water coolExamples from the Corpus
cooling tower• We have a monthly cooling tower water treatment with your company, the service consultant is John Norris.• Nothing breaches the flatness except some kind of smokestack or cooling tower a couple of miles to the north. 