Rock music is a broad genre of popular music that originated as "rock and roll" in the United States in the late 1940s and early 1950s, and developed into a range of different styles in the mid-1960s and later, particularly in the United States and the United Kingdom. It has its roots in the 1940s and 1950s rock and roll, a style which drew heavily from the genres of blues, rhythm, and blues, and from country music.
Country music, also known as country and western (or simply country), and hillbilly music, is a genre of popular music that takes its roots from genres such as blues and old-time music, and various types of American folk music including Appalachian, Cajun, and the cowboy Western music styles of Red Dirt, New Mexico, Texas country, and Tejano. Its popularized roots originate in the Southern United States of the early 1920s.
Pop music is a genre of popular music that originated in its modern forms in the US and the UK during the mid-1950s. The terms "popular music" and "pop music" are often used interchangeably, although the former describes all music that is popular and includes many diverse styles. "Pop" and "rock" were roughly synonymous terms until the late 1960s when they became quite separated from each other.