From Longman Dictionary of Contemporary Englishbrain drainˈbrain drain noun → the brain drain
Examples from the Corpus
brain drain• He could not argue, looking at Imperial, that there has been a major brain drain of senior staff.From Longman Business Dictionarybrain drainˈbrain drain noun [uncountable] the movement of highly skilled or professional people from their own country to another country where they can earn more moneyMany of the country’s top scientists have joined the brain drain to the US. 