ˌGang of ˈFour, the BrE AmE noun
a group of four Chinese Communist politicians, including Jiang Qing, who were leading supporters of the Cultural Revolution in China in the late 1960s. They were known for their violent actions and extreme ↑ left-wing ideas and they tried to take control of China after Mao Zedong’s death in 1976. Their attempt failed, and they were put in prison. If a group of four people, especially politicians, are considered to be a close group, newspapers sometimes call them the ‘Gang of Four’.