rima oris vs oral cavity

rima oris and oral cavity both are nouns.

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

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

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

Other synonyms of rima oris include mouth, oral fissure.

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