coronary sinus vs venous sinus

coronary sinus and venous sinus both are nouns.

Word	Noun	Adjective	Verb	Adverb
coronary sinus	Yes	No	No	No
venous sinus	Yes	No	No	No

As nouns, venous sinus is a hypernym of coronary sinus; that is, venous sinus is a word with a broader meaning than coronary sinus:

coronary sinus: a short sinus receiving most of the veins of the heart; empties into the right atrium
venous sinus: a wide channel containing blood; does not have the coating of an ordinary blood vessel

Other hypernyms of coronary sinus include sinus.

coronary sinus (noun)	venous sinus (noun)
a short sinus receiving most of the veins of the heart; empties into the right atrium	a wide channel containing blood; does not have the coating of an ordinary blood vessel