caldera vs crater

caldera and crater both are nouns.

Word	Noun	Adjective	Verb	Adverb
caldera	Yes	No	No	No
crater	Yes	No	No	No

As nouns, crater is a hypernym of caldera; that is, crater is a word with a broader meaning than caldera:

caldera: a large crater caused by the violent explosion of a volcano that collapses into a depression
crater: a bowl-shaped geological formation at the top of a volcano

Other hypernyms of caldera include volcanic crater.

caldera (noun)	crater (noun)
a large crater caused by the violent explosion of a volcano that collapses into a depression	a bowl-shaped depression formed by the impact of a meteorite or bomb
	a bowl-shaped geological formation at the top of a volcano