pit of the stomach vs epigastric fossa

pit of the stomach and epigastric fossa both are nouns.

Word	Noun	Adjective	Verb	Adverb
pit of the stomach	Yes	No	No	No
epigastric fossa	Yes	No	No	No

As nouns, pit of the stomach and epigastric fossa are synonyms defined as:

pit of the stomach and epigastric fossa: a slight depression in the midline just below the sternum (where a blow can affect the solar plexus)

pit of the stomach (noun)	epigastric fossa (noun)
a slight depression in the midline just below the sternum (where a blow can affect the solar plexus)	a slight depression in the midline just below the sternum (where a blow can affect the solar plexus)