is a specific kind of: caput, head.

is a broader term that covers: bullethead | attic, bean, bonce, dome, noggin, noodle.

has as a part: crown, pate, poll | scalp | occiput | sinciput | countenance, kisser, mug, phiz, physiognomy, smiler, visage.

is a part of: homo, human, human being, man.