epigastric vein vs vena

epigastric vein and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
epigastric vein	Yes	No	No	No
vena	Yes	No	No	No

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

epigastric vein: veins serving the anterior walls of the abdomen
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of epigastric vein include vein, venous blood vessel.

epigastric vein (noun)	vena (noun)
veins serving the anterior walls of the abdomen	a blood vessel that carries blood from the capillaries toward the heart