El Dorado vs imaginary place

El Dorado and imaginary place both are nouns.

Word	Noun	Adjective	Verb	Adverb
El Dorado	Yes	No	No	No
imaginary place	Yes	No	No	No

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

El Dorado: an imaginary place of great wealth and opportunity; sought in South America by 16th-century explorers
imaginary place: a place that exists only in imagination; a place said to exist in fictional or religious writings

Other hypernyms of El Dorado include fictitious place, mythical place.

El Dorado (noun)	imaginary place (noun)
an imaginary place of great wealth and opportunity; sought in South America by 16th-century explorers	a place that exists only in imagination; a place said to exist in fictional or religious writings