swelling vs caput

swelling and caput both are nouns.

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

As nouns, caput is a hyponym of swelling; that is, caput is a word with a more specific, narrower meaning than swelling:

swelling: something that bulges out or is protuberant or projects from its surroundings
caput: a headlike protuberance on an organ or structure

Other hyponyms of swelling include frontal eminence, occipital protuberance, belly, mogul, nub, nubble, snag, wart.

swelling (noun)	caput (noun)
the increase in volume of certain substances when they are heated (often accompanied by release of water)	the upper part of the human body or the front part of the body in animals; contains the face and brains
something that bulges out or is protuberant or projects from its surroundings	a headlike protuberance on an organ or structure
an abnormal protuberance or localized enlargement