paracosm vs phantasy world

paracosm and phantasy world both are nouns.

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

As nouns, phantasy world is a hypernym of paracosm; that is, phantasy 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
phantasy world: something existing solely in the imagination (but often mistaken for reality)

Other hypernyms of paracosm include fairyland, fantasy world.

paracosm (noun)	phantasy 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)