immigration vs aliyah

immigration and aliyah both are nouns.

Word	Noun	Adjective	Verb	Adverb
immigration	Yes	No	No	No
aliyah	Yes	No	No	No

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

immigration: migration into a place (especially migration to a country of which you are not a native in order to settle there)
aliyah: (Judaism) immigration of Jews to Israel

immigration (noun)	aliyah (noun)
migration into a place (especially migration to a country of which you are not a native in order to settle there)	(Judaism) immigration of Jews to Israel
the body of immigrants arriving during a specified interval	(Judaism) the honor of being called up to the reading desk in the synagogue to read from the Torah