rariora vs piece de resistance

rariora and piece de resistance both are nouns.

Word	Noun	Adjective	Verb	Adverb
rariora	Yes	No	No	No
piece de resistance	Yes	No	No	No

As nouns, piece de resistance is a hypernym of rariora; that is, piece de resistance is a word with a broader meaning than rariora:

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

Other hypernyms of rariora include collector's item, showpiece.

rariora (noun)	piece de resistance (noun)
(plural) rare collector's items	the outstanding item (the prize piece or main exhibit) in a collection
	the most important dish of a meal