ovarian vein vs vena

ovarian vein and vena both are nouns.

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

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

ovarian vein: one of the veins that drain the ovaries; the right opens into the inferior vena cava; the left opens into the left renal vein
vena: a blood vessel that carries blood from the capillaries toward the heart

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

ovarian vein (noun)	vena (noun)
one of the veins that drain the ovaries; the right opens into the inferior vena cava; the left opens into the left renal vein	a blood vessel that carries blood from the capillaries toward the heart