Elysium vs imaginary place

Elysium and imaginary place both are nouns.

Word	Noun	Adjective	Verb	Adverb
Elysium	Yes	No	No	No
imaginary place	Yes	No	No	No

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

Elysium: a place or condition of ideal happiness
imaginary place: a place that exists only in imagination; a place said to exist in fictional or religious writings

Other hypernyms of Elysium include fictitious place, mythical place.

Elysium (noun)	imaginary place (noun)
(Greek mythology) the abode of the blessed after death	a place that exists only in imagination; a place said to exist in fictional or religious writings
a place or condition of ideal happiness