Pop is a genre of popular music that originated in its modern form during the mid-1950s in the United States and the United Kingdom. The terms popular music and pop music are often used interchangeably, although the former describes all music that is popular and includes many disparate styles. During the 1950s and 1960s, pop music encompassed rock and roll and the youth-oriented styles it influenced. Rock and pop remained roughly synonymous until the late 1960s, after which pop became associated with music that was more commercial, ephemeral, and accessible.
Although much of the music that appears on record charts is seen as pop music, the genre is distinguished from chart music. Identifying factors usually include repeated choruses and hooks, short to medium-length songs written in a basic format, and rhythms or tempos that can be easily danced to. Much pop music also borrows elements from other styles such as rock, urban, dance, Latin, and country.