venula vs venous blood vessel

venula and venous blood vessel both are nouns.

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

As nouns, venous blood vessel is a hypernym of venula; that is, venous blood vessel is a word with a broader meaning than venula:

venula: a minute vein continuous with a capillary
venous blood vessel: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of venula include vein, vena.

venula (noun)	venous blood vessel (noun)
a minute vein continuous with a capillary	a blood vessel that carries blood from the capillaries toward the heart