Hip-hop (also known as rap music or simply rap) is a popular music genre that emerged in the early 1970s alongside an associated subculture in the African-American and Latino communities of New York City. The musical style is characterized by the synthesis of a wide range of techniques, but rapping is frequent enough that it has become a defining characteristic. Other key markers of the genre are the disc jockey (DJ), turntablism, scratching, beatboxing, and instrumental tracks. Cultural interchange has always been central to the hip-hop genre; it simultaneously borrows from its social environment while commenting on it.

The hip-hop genre and culture emerged from block parties in ethnic minority neighborhoods of New York City, particularly the Bronx. DJs began expanding the instrumental breaks of popular records when they noticed how excited it would make the crowds. The extended breaks provided a platform for break dancers and rappers. These breakbeats enabled the subsequent evolution of the hip-hop style. Many of the records used were disco due to its popularity at the time. This disco-inflected music was originally known as disco-rap and later described as "old-school hip-hop".

In the late 1980s and 1990s, hip-hop began to diversify as electro music started to inform a style later known as "new-school hip-hop". The transition between the mid-1980s and 1990s became known as "hip-hop's golden age", as the genre earned widespread critical acclaim and generated massive sales. Across the United States, several regional scenes emerged, most notably on the East and West Coasts, as well as in the South, which included the Houston, Atlanta and Memphis rap scenes. This era saw the emergence of popular styles such as G-funk, boom bap and gangsta rap, as well as more experimental genres like alternative hip-hop and jazz rap, which stemmed from the Native Tongues movement, alongside progressive and conscious hip-hop.

By the 2000s and 2010s, the popularity of hip-hop further expanded with the rise of internet rap, trap music, and Soundcloud rap, which led to several commercially successful artists. In 2017, hip-hop became the bestselling genre of popular music in the United States and had also developed its own regional variations around the world.

"Hip-hop" has been in use since the 17th century to mean a succession of hops. In George Villiers' 1671 play The Rehearsal, Prince Volscius exits a scene awkwardly with one boot on and the other off. The director of the scene exclaims, "to go off hip hop, hip hop, upon this occasion, is a thousand times better than any conclusion in the world".

A common variation on "hip hop" is "hippity hop", which was in wide usage by the 19th century. It appears in works like a poem from 1882 where four children sing, "Hippity hop to the candy Shop!" It was a common refrain in skipping games.

Many dance steps include a hop. By the 18th century, "hop" began to be used interchangeably with "dance" as both a noun and a verb.

An early usage of "hip hop" in recorded popular music is found in The Dovells' 1963 dance song "You Can't Sit Down", "...you gotta slop, bop, flip flop, hip hop, never stop". A decade later, Disco disc jockeys would pepper their sets with exhortations to the crowd, which is why the emerging style was originally known as "disco rap". One of DJ Hollywood's chants was "hip hop de hippy hop the body rock". Lovebug Starsky recalls originating the phrase when he messed up the change between records, "I picked up the mic and just started saying 'a hip hop, hip hop, de hibbyhibbyhibbyhibby hop'". He was claiming credit for inventing the name by 1979.