oral fissure vs rima

oral fissure and rima both are nouns.

Word	Noun	Adjective	Verb	Adverb
oral fissure	Yes	No	No	No
rima	Yes	No	No	No

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

oral fissure: the opening through which food is taken in and vocalizations emerge
rima: a narrow elongated opening or fissure between two symmetrical parts

oral fissure (noun)	rima (noun)
the opening through which food is taken in and vocalizations emerge	a narrow elongated opening or fissure between two symmetrical parts