paracosm vs fantasy world

paracosm and fantasy world both are nouns.

Word	Noun	Adjective	Verb	Adverb
paracosm	Yes	No	No	No
fantasy world	Yes	No	No	No

As nouns, fantasy world is a hypernym of paracosm; that is, fantasy world is a word with a broader meaning than paracosm:

paracosm: a prolonged fantasy world invented by children; can have a definite geography and language and history
fantasy world: something existing solely in the imagination (but often mistaken for reality)

Other hypernyms of paracosm include fairyland, phantasy world.

paracosm (noun)	fantasy world (noun)
a prolonged fantasy world invented by children; can have a definite geography and language and history	something existing solely in the imagination (but often mistaken for reality)