Chill-out music (sometimes also chillout, chill out, or simply chill) is an umbrella term for several styles of electronic music characterized by their mellow style and mid-tempo beats — "chill" being derived from a slang injunction to "relax."

Chill out music emerged in the early and mid-1990s in "chill rooms" at dance clubs, where relaxing music was played to allow dancers a chance to "chill out" from the more emphatic and fast-tempo music played on the main dance floor.

Stylistic origins Classical music, ambient, electronica
Cultural origins Early-1990s, Europe