Hypnagogic pop (or simply h-pop) is a loosely defined style of pop and psychedelic music that evokes cultural memory and nostalgia for the popular entertainment of the past (principally the 1980s). It emerged in the mid to late 2000s out of the American post-noise underground as Gen X lo-fi and noise musicians began adopting retro aesthetics from their childhood, such as radio and soft rock, new wave music, video game music, synth-pop and R&B. Recordings were typically marked by the use of outmoded analog equipment and DIY experimentation, while distributed on cassettes and CD-R's with circulation primarily based on the Internet through blog sites.
The genre's name was coined by journalist David Keenan in an August 2009 issue of The Wire to label the developing trend, which he characterized as "pop music refracted through the memory of a memory." It was used interchangeably with "chillwave" or "glo-fi" and gained critical attention through artists such as Ariel Pink and James Ferraro. The music has been variously described as a 21st-century update of psychedelia, a reappropriation of media-saturated capitalist culture, and an "American cousin" to British hauntology.