fontanelle vs orifice

fontanelle and orifice both are nouns.

Word	Noun	Adjective	Verb	Adverb
fontanelle	Yes	No	No	No
orifice	Yes	No	No	No

As nouns, orifice is a hypernym of fontanelle; that is, orifice is a word with a broader meaning than fontanelle:

fontanelle: any membranous gap between the bones of the cranium in an infant or fetus
orifice: an aperture or hole that opens into a bodily cavity

Other hypernyms of fontanelle include opening, porta.

fontanelle (noun)	orifice (noun)
any membranous gap between the bones of the cranium in an infant or fetus	an aperture or hole that opens into a bodily cavity