Pop music (a term that originally derives from an abbreviation of "popular") is a genre of popular music which originated in its modern form in the 1950s, deriving from rock and roll. The terms popular music and pop music are often used interchangeably, even though the former is a description of music which is popular (and can include any style), whilst the latter is a specific genre containing qualities of mass appeal.
As a genre, pop music is very eclectic, often borrowing elements from other styles including urban, dance, rock, Latin and country; nonetheless, there are core elements which define pop. Such include generally short-to-medium length songs, written in a basic format (often the verse-chorus structure), as well as the common employment of repeated choruses, melodic tunes, and catchy hooks.
So-called "pure pop" music, such as power pop, features all these elements, utilising electric guitars, drums and bass for instrumentation; in the case of such music, the main goal is usually that of being pleasurable to listen to, rather than having much artistic depth. Pop music is generally thought of as a genre which is commercially recorded and desires to have a mass audience appeal.
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 it is not the sum of all chart music, which has always contained songs from a variety of sources, including classical, jazz, rock, and novelty songs, while pop music as a genre is usually seen as existing and developing separately. Thus "pop music" may be used to describe a distinct genre, aimed at a youth market, often characterized as a softer alternative to rock and roll.