Rock

Rock music is a genre of popular music that entered the mainstream in the 1950s. It has its roots in 1940s and 1950s rock and roll, rhythm and blues, country music and also drew on folk music, jazz and classical music. The sound of rock often revolves around the electric guitar, a back beat laid down by a rhythm section of electric bass guitar, drums, and keyboard instruments such as Hammond organ, piano, or, since the 1970s, synthesizers. Along with the guitar or keyboards, saxophone and blues-style harmonica are sometimes used as soloing instruments. In its "purest form", it "has three chords, a strong, insistent back beat, and a catchy melody."
                        – from Wikipedia