migration/maɪˈgreɪʃn; maɪ`ɡreʃən/ n(a) (also transmigration) [C, U](action of) migrating 迁居; 移居; 迁徙.(b) [C] number of migrating people, animals, etc 迁徙的人、 动物等的数量 a huge migration of people into Europe 大量涌至欧洲的移民.
牛津英汉双解词典