oral cavity vs rima oris

oral cavity and rima oris both are nouns.

Word	Noun	Adjective	Verb	Adverb
oral cavity	Yes	No	No	No
rima oris	Yes	No	No	No

As nouns, oral cavity and rima oris are synonyms defined as:

oral cavity and rima oris: the opening through which food is taken in and vocalizations emerge

Other synonyms of oral cavity include mouth, oral fissure.

oral cavity (noun)	rima oris (noun)
the opening through which food is taken in and vocalizations emerge	the opening through which food is taken in and vocalizations emerge