Pop music is usually understood to be commercially recorded music, often oriented toward a youth market, usually consisting of relatively short, simple songs utilizing technological innovations to produce new variations on existing themes.
David Hatch and Stephen Millward define pop music as "a body of music which is distinguishable from popular, jazz and folk musics". Although pop music is often seen as oriented towards the singles charts

Record chart

A record chart is a ranking of recorded music according to popularity during a given period of time. Examples of music charts are the Hit parade, Hot 100 or Top 40....

 it is not the sum of all chart music, which has always contained songs from a variety of sources, including classical

Classical music

Classical music is the art music produced in, or rooted in, the traditions of Western liturgical and secular music, encompassing a broad period from roughly the 11th century to present times...

, jazz

Jazz

Jazz is a musical style that originated at the beginning of the 20th century in African American communities in the Southern United States. It was born out of a mix of African and European music traditions. From its early development until the present, jazz has incorporated music from 19th and 20th...

, rock

Rock music

Rock music is a genre of popular music that developed during and after the 1960s, particularly in the United Kingdom and the United States. It has its roots in 1940s and 1950s rock and roll, itself heavily influenced by rhythm and blues and country music...

, and novelty song

Novelty song

A novelty song is a comical or nonsensical song, performed principally for its comical effect. Humorous songs, or those containing humorous elements, are not necessarily novelty songs. The term arose in Tin Pan Alley to describe one of the major divisions of popular music. The other two divisions...

s, while pop music as a genre is usually seen as existing and developing separately.