Longman Dictionary of Contemporary English
brain drainˈbrain drain BrE AmE noun
the brain drain a movement of highly skilled or professional people from their own country to a country where they can earn more money
Oxford Advanced Learner's Dictionary
brain drain
ˈbrain drain [brain drain brain drains] noun singular (informal)
the movement of highly skilled and qualified people to a country where they can work in better conditions and earn more money
• a brain drain to the US
Cambridge Advanced Learner's Dictionary
Cambridge Advanced Learner's Dictionary - 4th Edition
ˈ brain ˌ drain noun [ S ]
the situation in which large numbers of educated and very skilled people leave their own country to live and work in another one where pay and conditions are better:
Britain has suffered a huge brain drain in recent years.
© Cambridge University Press 2013
Collins Advanced Learner’s English Dictionary
brain drain
When people talk about a brain drain, they are referring to the movement of a large number of scientists or academics away from their own country to other countries where the conditions and salaries are better.
N-SING
Merriam-Webster's Advanced Learner's Dictionary
brain drain
brain drain noun [singular] : a situation in which many educated or professional people leave a particular place or profession and move to another one that gives them better pay or living conditions
• Nothing has been done to stop the brain drain as more and more doctors move away from the area.