passageway vs sinus

passageway and sinus both are nouns.

Word	Noun	Adjective	Verb	Adverb
passageway	Yes	No	No	No
sinus	Yes	No	No	No

As nouns, sinus is a hyponym of passageway; that is, sinus is a word with a more specific, narrower meaning than passageway:

passageway: a path or channel or duct through or along which something may pass
sinus: an abnormal passage leading from a suppurating cavity to the body surface

passageway (noun)	sinus (noun)
a passage between rooms or between buildings	a wide channel containing blood; does not have the coating of an ordinary blood vessel
a path or channel or duct through or along which something may pass	any of various air-filled cavities especially in the bones of the skull
	an abnormal passage leading from a suppurating cavity to the body surface