bunion vs swelling

bunion and swelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
bunion	Yes	No	No	No
swelling	Yes	No	No	No

As nouns, swelling is a hypernym of bunion; that is, swelling is a word with a broader meaning than bunion:

Other hypernyms of bunion include lump, puffiness.

bunion (noun)	swelling (noun)
a painful swelling of the bursa of the first joint of the big toe	the increase in volume of certain substances when they are heated (often accompanied by release of water)
	something that bulges out or is protuberant or projects from its surroundings
	an abnormal protuberance or localized enlargement