saphenous vein vs vena

saphenous vein and vena both are nouns.

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

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

saphenous vein: either of two chief superficial veins of the leg that drain blood from the foot
vena: a blood vessel that carries blood from the capillaries toward the heart

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

saphenous vein (noun)	vena (noun)
either of two chief superficial veins of the leg that drain blood from the foot	a blood vessel that carries blood from the capillaries toward the heart