gibbousness vs belly

gibbousness and belly both are nouns.

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

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

gibbousness: something that bulges out or is protuberant or projects from its surroundings
belly: a part that bulges deeply

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

gibbousness (noun)	belly (noun)
something that bulges out or is protuberant or projects from its surroundings	the underpart of the body of certain vertebrates such as snakes or fish
	the region of the body of a vertebrate between the thorax and the pelvis
	a protruding abdomen
	the hollow inside of something
	a part that bulges deeply

gibbousness (verb)	belly (verb)
	swell out or bulge out