emigration
n.
1640s, from Late Latin emigrationem (nominative emigratio) "removal from a place," noun of action from past participle stem of Latin emigrare "move away, depart from a place," from assimilated form of ex- "out" (see ex-) + migrare "to move" (see migration).
〔蒋〕[migr=remove，move迁移，-ation名词后缀] 移居，移民出境