From Longman Business Dictionarycompulsory purchasecomˌpulsory ˈpurchase (also compulsory acquisition) noun [uncountable] LAW in Britain, when a government organization has the legal power to make you sell them your land or property and pays you an amount of money as COMPENSATION. This usually happens when a new road etc is being builtThe Local Authority had certain powers of compulsory purchase in relation to land near the motorway.