epicardium vs visceral pericardium

epicardium and visceral pericardium both are nouns.

Word	Noun	Adjective	Verb	Adverb
epicardium	Yes	No	No	No
visceral pericardium	Yes	No	No	No

As nouns, epicardium and visceral pericardium are synonyms defined as:

epicardium and visceral pericardium: the innermost of the two layers of the pericardium

epicardium (noun)	visceral pericardium (noun)
the innermost of the two layers of the pericardium	the innermost of the two layers of the pericardium