Rock is a broad genre of popular music that originated in the United States as "rock and roll" in the late 1940s and early 1950s, developing into a range of different styles from the mid-1960s, primarily in the United States and the United Kingdom. It has its roots in rock and roll, a style that drew directly from the black musical genres of blues, rhythm and blues, and country music. Rock also drew strongly from genres such as electric blues and folk, and incorporated influences from jazz and other musical styles. For instrumentation, rock is typically centered on the electric guitar, usually as part of a rock group with electric bass guitar, drums, and one or more singers. Usually, rock is song-based music with a time signature and using a verse–chorus form, but the genre has become extremely diverse. Like pop music, lyrics often stress romantic love but also address a wide variety of other themes that are frequently social or political. Rock was the most popular genre of music in the U.S. and much of the Western world from the 1950s until its decline in the 2010s. Wikipedia