progressive rock vs rock music

progressive rock and rock music both are nouns.

Word	Noun	Adjective	Verb	Adverb
progressive rock	Yes	No	No	No
rock music	Yes	No	No	No

As nouns, rock music is a hypernym of progressive rock; that is, rock music is a word with a broader meaning than progressive rock:

progressive rock: a style of rock music that emerged in the 1970s; associated with attempts to combine rock with jazz and other forms; intended for listening and not dancing
rock music: a genre of popular music originating in the 1950s; a blend of black rhythm-and-blues with white country-and-western

Other hypernyms of progressive rock include rock-and-roll, rock'n'roll, rock 'n' roll, rock, rock and roll.

progressive rock (noun)	rock music (noun)
a style of rock music that emerged in the 1970s; associated with attempts to combine rock with jazz and other forms; intended for listening and not dancing	a genre of popular music originating in the 1950s; a blend of black rhythm-and-blues with white country-and-western