piece de resistance vs curio

piece de resistance and curio both are nouns.

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

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

piece de resistance: the outstanding item (the prize piece or main exhibit) in a collection
curio: something unusual -- perhaps worthy of collecting

Other hypernyms of piece de resistance include curiosity, oddity, oddment, peculiarity, rarity.

piece de resistance (noun)	curio (noun)
the outstanding item (the prize piece or main exhibit) in a collection	something unusual -- perhaps worthy of collecting
the most important dish of a meal