n.

1. 遷移；（候鳥等的）遷徙[U][C]
   There has been a migration of people from the country to the towns.

   人們從鄉下移居城鎮。

   the annual migration of birds

   候鳥每年的遷徙

2. 移民群；移棲動物群[C]
   Ornithologists like to study the migration of birds.

   鳥類學家喜歡研究鳥的移棲動物群的行為。

3. 【化】【物】移動，徙動