think tank
noun [ C ]
ukusa group of experts who are brought together to develop ideas and give advice on a particular subject:
corporate/economic/political think tank Investor confidence in Japan dropped to its lowest level in 16 months, according to a leading economic think tank.
think-tanker
noun [ C ] (also think tanker)
The Conference brings politicians, businessmen, and think-tankers together every year for debate on the economy.