bulge vs caput

bulge and caput both are nouns.

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

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

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

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

bulge (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

bulge (verb)	caput (verb)
swell or protrude outwards
cause to bulge or swell outwards
bulge outward
bulge out; form a bulge outward, or be so full as to appear to bulge