opus vs passage

opus and passage both are nouns.

Word	Noun	Adjective	Verb	Adverb
opus	Yes	No	No	No
passage	Yes	No	No	No

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

opus (noun)	passage (noun)
a musical work that has been created	a journey usually by ship
	the passing of a law by a legislative body
	the act of passing something to another person
	the act of passing from one state or place to the next
	a bodily reaction of changing from one place or stage to another
	a way through or along which someone or something may pass
	a path or channel or duct through or along which something may pass
	a section of text; particularly a section of medium length
	a short section of a musical composition
	the motion of one object relative to another