cardia vs orifice

cardia and orifice both are nouns.

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

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

cardia: the opening into the stomach and that part of the stomach connected to the esophagus
orifice: an aperture or hole that opens into a bodily cavity

Other hypernyms of cardia include opening, porta.

cardia (noun)	orifice (noun)
the opening into the stomach and that part of the stomach connected to the esophagus	an aperture or hole that opens into a bodily cavity