capillary vein vs vena

capillary vein and vena both are nouns.

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

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

capillary vein: a minute vein continuous with a capillary
vena: a blood vessel that carries blood from the capillaries toward the heart

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

capillary vein (noun)	vena (noun)
a minute vein continuous with a capillary	a blood vessel that carries blood from the capillaries toward the heart