fontanel vs orifice

fontanel and orifice both are nouns.

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

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

fontanel: 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 fontanel include opening, porta.

fontanel (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