vena sigmoideus vs sigmoid vein

vena sigmoideus and sigmoid vein both are nouns.

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

As nouns, vena sigmoideus and sigmoid vein are synonyms defined as:

vena sigmoideus and sigmoid vein: tributaries of the inferior mesenteric vein; drains the sigmoid colon

vena sigmoideus (noun)	sigmoid vein (noun)
tributaries of the inferior mesenteric vein; drains the sigmoid colon	tributaries of the inferior mesenteric vein; drains the sigmoid colon