migration vs emigration

migration and emigration both are nouns.

Word	Noun	Adjective	Verb	Adverb
migration	Yes	No	No	No
emigration	Yes	No	No	No

As nouns, emigration is a hyponym of migration; that is, emigration is a word with a more specific, narrower meaning than migration:

migration: the movement of persons from one country or locality to another
emigration: migration from a place (especially migration from your native country in order to settle in another)

Other hyponyms of migration include expatriation, out-migration, immigration, in-migration, gold rush.

migration (noun)	emigration (noun)
the movement of persons from one country or locality to another	migration from a place (especially migration from your native country in order to settle in another)
the periodic passage of groups of animals (especially birds or fishes) from one region to another for feeding or breeding
(chemistry) the nonrandom movement of an atom or radical from one place to another within a molecule
a group of people migrating together (especially in some given time period)