Definition of migrations:
(n) :
An instance of moving to live in another place for a while.
(n) :
Seasonal moving of animals, as mammals, birds or fish, especially between breeding and non-breeding areas.
(n) :
Movement in general.
(n) :
(computing) Instance of changing a platform from an environment to another one.
(n) :
(biochemistry) The movement of cells in particular directions to specific locations.