rock music vs rock-and-roll

rock music and rock-and-roll both are nouns.

Word	Noun	Adjective	Verb	Adverb
rock music	Yes	No	No	No
rock-and-roll	Yes	No	No	No

As nouns, rock music and rock-and-roll are synonyms defined as:

rock music and rock-and-roll: a genre of popular music originating in the 1950s; a blend of black rhythm-and-blues with white country-and-western

Other synonyms of rock music include rock'n'roll, rock 'n' roll, rock, rock and roll.

rock music (noun)	rock-and-roll (noun)
a genre of popular music originating in the 1950s; a blend of black rhythm-and-blues with white country-and-western	a genre of popular music originating in the 1950s; a blend of black rhythm-and-blues with white country-and-western