curio vs curiosity

curio and curiosity both are nouns.

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

As nouns, curio and curiosity are synonyms defined as:

Other synonyms of curio include oddity, oddment, peculiarity, rarity.

curio (noun)	curiosity (noun)
something unusual -- perhaps worthy of collecting	something unusual -- perhaps worthy of collecting
	a state in which you want to learn more about something