Psychedelic rock and Rock and roll

Psychedelic rock noun - A musical style that emerged in the 1960s; rock music inspired by or related to drug-induced experience.

Rock and roll and psychedelic rock are semantically related. In some cases you can use "Rock and roll" instead a noun phrase "Psychedelic rock".

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.

Psychedelic rock and rock and roll are semantically related. Sometimes you can replace phrase "Psychedelic rock" with "Rock and roll", this phrases are similar.