To answer this here are some dictionary meanings -
Rock Music
noun
[mass noun]- a form of popular music which evolved from rock and roll and pop music during the mid and late 1960s . Harsher and often self-consciously more serious than its predecessors, it was initially characterized by musical experimentation and drug-related or anti-establishment lyrics.
- another term for rock and roll
Rock and roll
(also rock 'n' roll)
noun
[mass noun] a type of popular dance music originating in the 1950s , characterized by a heavy beat and simple melodies. Rock and roll was an amalgam of black rhythm and blues and white country music, usually based around a twelve-bar structure and an instrumentation of guitar, double bass, and drums.Pop Music
Pronunciation:/pɒp/
noun
- (also pop music)[mass noun] commercial popular music, in particular accessible, tuneful music of a kind popular since the 1950s and sometimes contrasted with rock, soul, or other forms of popular music.
adjective
[attributive] 1 relating to commercial popular music:a pop star
a pop group