Elysium vs Heaven

Elysium and Heaven both are nouns.

Word	Noun	Adjective	Verb	Adverb
Elysium	Yes	No	No	No
Heaven	Yes	No	No	No

As nouns, Heaven is a hypernym of Elysium; that is, Heaven is a word with a broader meaning than Elysium:

Elysium: (Greek mythology) the abode of the blessed after death
Heaven: a place regarded by various beliefs as the abode of their deities; also a place where good people are believed to go after death

Elysium (noun)	Heaven (noun)
(Greek mythology) the abode of the blessed after death	a place regarded by various beliefs as the abode of their deities; also a place where good people are believed to go after death
a place or condition of ideal happiness