common facial vein vs vena

common facial vein and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
common facial vein	Yes	No	No	No
vena	Yes	No	No	No

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

common facial vein: vein formed by union of facial vein and the retromandibular vein and emptying into the jugular vein
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of common facial vein include vein, venous blood vessel.

common facial vein (noun)	vena (noun)
vein formed by union of facial vein and the retromandibular vein and emptying into the jugular vein	a blood vessel that carries blood from the capillaries toward the heart