rariora vs collector's item

rariora and collector's item both are nouns.

Word	Noun	Adjective	Verb	Adverb
rariora	Yes	No	No	No
collector's item	Yes	No	No	No

As nouns, collector's item is a hypernym of rariora; that is, collector's item is a word with a broader meaning than rariora:

rariora: (plural) rare collector's items
collector's item: the outstanding item (the prize piece or main exhibit) in a collection

Other hypernyms of rariora include piece de resistance, showpiece.

rariora (noun)	collector's item (noun)
(plural) rare collector's items	the outstanding item (the prize piece or main exhibit) in a collection