innominate vein vs vena

innominate vein and vena both are nouns.

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

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

innominate vein: veins formed by the union of the internal jugular and subclavian veins
vena: a blood vessel that carries blood from the capillaries toward the heart

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

innominate vein (noun)	vena (noun)
veins formed by the union of the internal jugular and subclavian veins	a blood vessel that carries blood from the capillaries toward the heart