migration

Noun (4)migrations

1. the movement of persons from one country or locality to anotherType of motion, movementKinds emigration, immigration, gold rush
2. a group of people migrating together (especially in some given time period)Type of people
3. (chemistry) the nonrandom movement of an atom or radical from one place to another within a moleculeType of event
4. the periodic passage of groups of animals (especially birds or fishes) from one region to another for feeding or breedingType of periodic event, recurrent event