vena hepatica vs vena

vena hepatica and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
vena hepatica	Yes	No	No	No
vena	Yes	No	No	No

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

vena hepatica: a vein that drains the liver; empties into the vena cava
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of vena hepatica include vein, venous blood vessel.

vena hepatica (noun)	vena (noun)
a vein that drains the liver; empties into the vena cava	a blood vessel that carries blood from the capillaries toward the heart