hemorrhoidal vein vs vena

hemorrhoidal vein and vena both are nouns.

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

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

hemorrhoidal vein: any of several veins draining the walls of the anal canal and rectum
vena: a blood vessel that carries blood from the capillaries toward the heart

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

hemorrhoidal vein (noun)	vena (noun)
any of several veins draining the walls of the anal canal and rectum	a blood vessel that carries blood from the capillaries toward the heart