venae renis vs vena

venae renis and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
venae renis	Yes	No	No	No
vena	Yes	No	No	No

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

venae renis: veins of the kidney; drain the kidney into the renal vein
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of venae renis include vein, venous blood vessel.

venae renis (noun)	vena (noun)
veins of the kidney; drain the kidney into the renal vein	a blood vessel that carries blood from the capillaries toward the heart