vena vs venous blood vessel

vena and venous blood vessel both are nouns.

Word	Noun	Adjective	Verb	Adverb
vena	Yes	No	No	No
venous blood vessel	Yes	No	No	No

As nouns, vena and venous blood vessel are synonyms defined as:

vena and venous blood vessel: a blood vessel that carries blood from the capillaries toward the heart

Other synonyms of vena include vein.

vena (noun)	venous blood vessel (noun)
a blood vessel that carries blood from the capillaries toward the heart	a blood vessel that carries blood from the capillaries toward the heart