Characteristics and etymology
Much pop and rock music has been very similar in sound, instrumentation and even lyrical content. The terms "pop rock" and "power pop" have been used to describe more commercially successful music that uses elements from, or the form of, rock music. Writer Johan Fornas views pop/rock as "one single, continuous genre field", rather than distinct categories. To the authors Larry Starr and Christopher Waterman, it is defined as an "upbeat variety of rock music" represented by artists and bands such as: Andy Kim, the Bells, Paul McCartney, Lighthouse, and Peter Frampton.
The term pop has been used since the early twentieth century to refer to popular music in general, but from the mid-1950s it began to be used for a distinct genre, aimed at a youth market, often characterized as a softer alternative to rock and roll. In the aftermath of the British Invasion, from about 1967, it was increasingly used in opposition to the term rock music, to describe a form that was more commercial, ephemeral and accessible.
As of the 2010s, guitar pop rock and indie rock are roughly synonymous terms.