cystic vein vs vena

cystic vein and vena both are nouns.

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

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

cystic vein: vein that drains the gallbladder
vena: a blood vessel that carries blood from the capillaries toward the heart

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

cystic vein (noun)	vena (noun)
vein that drains the gallbladder	a blood vessel that carries blood from the capillaries toward the heart