From Longman Dictionary of Contemporary Englishconcentration campˌconcenˈtration ˌcamp noun [countable] SCJa prison where political prisoners and other people who are not soldiers are kept and treated cruelly, especially during a war
Examples from the Corpus
concentration camp• You look as if you've been in a concentration camp you do! and that's the truth.• In 1944 the woman was betrayed and imprisoned in a concentration camp.• What really struck me was that I looked like a concentration camp prisoner.• Alexander Schweidler, 78, a former concentration camp guard who settled in Britain, died after a heart attack.• April 18: Had that lousy dream about packing up for the concentration camp and the clock going dead. 