vena sigmoideus vs vena

vena sigmoideus and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
vena sigmoideus	Yes	No	No	No
vena	Yes	No	No	No

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

vena sigmoideus: tributaries of the inferior mesenteric vein; drains the sigmoid colon
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of vena sigmoideus include vein, venous blood vessel.

vena sigmoideus (noun)	vena (noun)
tributaries of the inferior mesenteric vein; drains the sigmoid colon	a blood vessel that carries blood from the capillaries toward the heart