Migration

[mahy-grey-shuh n] /maɪˈgreɪ ʃən/

noun
1.
the process or act of .
2.
a migratory movement:
preparations for the migration.
3.
a number or body of persons or animals together.
4.
Chemistry. a movement or change of position of atoms within a molecule.
5.
Physics. (def 3a).
/maɪˈɡreɪʃən/
noun
1.
the act or an instance of migrating
2.
a group of people, birds, etc, migrating in a body
3.
(chem) a movement of atoms, ions, or molecules, such as the motion of ions in solution under the influence of electric fields
n.

1610s, of persons, 1640s of animals, from Latin migrationem (nominative migratio) “a removal, change of abode, migration,” noun of action from past participle stem of migrare “to move from one place to another,” probably originally *migwros, from PIE *meigw- (cf. Greek ameibein “to change”), from root *mei- “to change, go, move” (see mutable). Related: Migrational.

That European birds migrate across the seas or to Asia was understood in the Middle Ages, but subsequently forgotten. Dr. Johnson held that swallows slept all winter in the beds of rivers, while the naturalist Morton (1703) stated that they migrated to the moon. As late as 1837 the “Kendal Mercury” “detailed the circumstance of a person having observed several Swallows emerging from Grasmere Lake, in the spring of that year, in the form of ‘bell-shaped bubbles,’ from each of which a Swallow burst forth ….”

migration mi·gra·tion (mī-grā’shən)
n.

migration
(mī-grā’shən)