showpiece vs curiosity

showpiece and curiosity both are nouns.

Word	Noun	Adjective	Verb	Adverb
showpiece	Yes	No	No	No
curiosity	Yes	No	No	No

As nouns, curiosity is a hypernym of showpiece; that is, curiosity is a word with a broader meaning than showpiece:

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

Other hypernyms of showpiece include curio, oddity, oddment, peculiarity, rarity.

showpiece (noun)	curiosity (noun)
the outstanding item (the prize piece or main exhibit) in a collection	something unusual -- perhaps worthy of collecting
	a state in which you want to learn more about something