maw vs rima oris

maw and rima oris both are nouns.

Word	Noun	Adjective	Verb	Adverb
maw	Yes	No	No	No
rima oris	Yes	No	No	No

As nouns, rima oris is a hypernym of maw; that is, rima oris is a word with a broader meaning than maw:

maw: informal terms for the mouth
rima oris: the opening through which food is taken in and vocalizations emerge

Other hypernyms of maw include mouth, oral cavity, oral fissure.

maw (noun)	rima oris (noun)
informal terms for the mouth	the opening through which food is taken in and vocalizations emerge