music of the spheres vs euphony

music of the spheres and euphony both are nouns.

Word	Noun	Adjective	Verb	Adverb
music of the spheres	Yes	No	No	No
euphony	Yes	No	No	No

As nouns, euphony is a hypernym of music of the spheres; that is, euphony is a word with a broader meaning than music of the spheres:

music of the spheres: an inaudible music that Pythagoras thought was produced by the celestial
euphony: any agreeable (pleasing and harmonious) sounds

Other hypernyms of music of the spheres include music.

music of the spheres (noun)	euphony (noun)
an inaudible music that Pythagoras thought was produced by the celestial	any agreeable (pleasing and harmonious) sounds