epigastric fossa vs fossa

epigastric fossa and fossa both are nouns.

Word	Noun	Adjective	Verb	Adverb
epigastric fossa	Yes	No	No	No
fossa	Yes	No	No	No

As nouns, fossa is a hypernym of epigastric fossa; that is, fossa is a word with a broader meaning than epigastric fossa:

epigastric fossa: a slight depression in the midline just below the sternum (where a blow can affect the solar plexus)
fossa: a concavity in a surface (especially an anatomical depression)

Other hypernyms of epigastric fossa include pit.

epigastric fossa (noun)	fossa (noun)
a slight depression in the midline just below the sternum (where a blow can affect the solar plexus)	largest carnivore of Madagascar; intermediate in some respects between cats and civets
	a concavity in a surface (especially an anatomical depression)