passage vs modulation

passage and modulation both are nouns.

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

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

passage (noun)	modulation (noun)
a journey usually by ship	the act of modifying or adjusting according to due measure and proportion (as with regard to artistic effect)
the passing of a law by a legislative body	(electronics) the transmission of a signal by using it to vary a carrier wave; changing the carrier's amplitude or frequency or phase
the act of passing something to another person	a musical passage moving from one key to another
the act of passing from one state or place to the next	rise and fall of the voice pitch
a bodily reaction of changing from one place or stage to another	a manner of speaking in which the loudness or pitch or tone of the voice is modified
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