human head vs caput

human head and caput both are nouns.

Word	Noun	Adjective	Verb	Adverb
human head	Yes	No	No	No
caput	Yes	No	No	No

As nouns, caput is a hypernym of human head; that is, caput is a word with a broader meaning than human head:

human head: the head of a human being
caput: the upper part of the human body or the front part of the body in animals; contains the face and brains

Other hypernyms of human head include head.

human head (noun)	caput (noun)
the head of a human being	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