動詞 migrate:

1. move from one country or region to another and settle there
   同義詞：transmigrate
2. move periodically or seasonally

1. To all appearance, Mr. Li is going to migrate.
   李先生顯然是要移民了。
2. In winter many of our birds migrate form here to warmer countries.
   我們有許多鳥兒冬天從這里遷移到比較溫暖的國家去。
3. In some developing countries more and more people migrate to urban area.
   在某些發(fā)展中的國家，越來越多的人向市區(qū)遷移。
4. Some tribes migrate with their cattle in search of fresh grass.
   有些部落為了尋找新鮮的牧草而帶著他們的牲畜遷移。

mi.grate

v.intr.（不及物動詞）
mi.grat.ed,mi.grat.ing,mi.grates
To move from one country or region and settle in another.
移居，遷徙：從一個國家或地區(qū)遷移到另一個國家或地區(qū)定居
To change location periodically, especially by moving seasonally from one region to another.
遷移，移棲：定期變換所在地，尤指季節(jié)性地從一地遷移到另一地

來源：
Latin migr3re migr3t- * see mei-
拉丁語 migr3re migr3t- *參見 mei-

【引伸】
mi.gra.tor
n.（名詞）
Migrate, which is used of people and animals, sometimes implies a lack of permanent settlement,especially as a result of seasonal or periodic movement.Emigrate and immigrate are used only of people and imply a permanent move,generally across a political boundary.Emigrate describes the move relative to the point of departure:
Migrate 用于人和動物， 有時含有缺乏永久的居住地之意，尤指出于季節(jié)性或定期遷移這兩個原因。Emigrate 和 immigrate 僅用來指人， 意味著永久性的遷移，一般指越過政治意義上的疆界。Emigrate 的含義與離開有關(guān)：
例句：
After the Nazis came to power in Germany, many scientists emigrated (that is, left Germany).
納粹奪取了德國的政權(quán)之后，許多科學(xué)家都遷走了（也就是說，離開了德國）。

By contrast,immigrate describes the move relative to the destination:
與之相對，immigrate 指的是與到達(dá)目的有關(guān)的移動：
例句：
The promise of prosperity in the United States encouraged many people to immigrate (that is, move to the United States).
興旺發(fā)達(dá)的前景吸引了眾多的移民到美國（也就是指，遷入了美國）