gibbousness vs caput

gibbousness and caput both are nouns.

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

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

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

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

gibbousness (noun)	caput (noun)
something that bulges out or is protuberant or projects from its surroundings	the upper part of the human body or the front part of the body in animals; contains the face and brains
	a headlike protuberance on an organ or structure