eldorado vs fictitious place

eldorado and fictitious place both are nouns.

Word	Noun	Adjective	Verb	Adverb
eldorado	Yes	No	No	No
fictitious place	Yes	No	No	No

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

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

Other hypernyms of eldorado include imaginary place, mythical place.

eldorado (noun)	fictitious 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