roller coast·er/ˈ·· ˌ··/ n [C] 1 a track with sudden steep slopes and curves, that people ride on in special vehicles for fun at FAIRs 〔游乐园中的〕过山车，云霄飞车 2 a situation that is impossible to control because it keeps changing very quickly 急转突变、难以控制的情况: the story of two women's lives riding a rollercoaster of love, revenge and murder 两个女人变幻莫测，由爱情、报复、谋杀交织成的人生故事