n.
1.the movement of persons from one country or locality to another
2.a group of people migrating together (especially in some given time period)
3.(chemistry) the nonrandom movement of an atom or radical from one place to another within a molecule
4.the periodic passage of groups of animals (especially birds or fishes) from one region to another for feeding or breeding
Idiom of the Day
to a fault
to do something so very well or to be something so good that it is almost bad
My friend is honest to a fault and will not say anything unless it is the absolute truth.