A musical genre that incorporates elements of a number of different styles - including jazz, electronic music, new age, modern classical music, traditional, world and noise. It is sometimes characterised as possessing a sense of resonant sonic space and of being designed to function equally effectively for both passive (background music) and active listening.

The term was first coined by Brian Eno in the mid-1970s to refer to music that would envelop the listener without drawing attention to itself, that can be either "actively listened to with attention or as easily ignored, depending on the choice of the listener" (Eno termed his experiments in sound as 'treatments' rather than as traditional performances).

Many of the works of French composers Erik Satie and Edgard Varèse are regarded as predecessors to ambient music. John Cage created the ultimate ambient work with his 4'33", three periods of silence first played on the piano, which make the audience listen to the ambient sound surrounding them. Cage-inspired minimalist composers such as La Monte Young, Morton Feldman, Terry Riley, Steve Reich and Philip Glass also influenced Eno's groundbreaking style, and ambient music can be seen as a kind of minimalism.

Early albums by Pink Floyd (such as Ummagumma and Meddle) and by krautrock artists such as Tangerine Dream and Popol Vuh greatly influenced the genre.

In the 1970s, some ambient artists who were influenced by new age spirituality created the eclectic genre known as new age music. By the 1980s, new age music had become so much better known than ambient music, that ambient was taken as a synonym for new age and many ambient musicians deliberately took on new age themes to market themselves to this audience.

Beginning in the 1980s, ambient music influenced some pop bands (examples can be found among instrumentals by New Order, Depeche Mode, Simple Minds and U2).

Later, electronic dance music and synth pop merged in many artists' works with the dreamy, meandering sound of Eno-style ambient music. Under the guise of various styles, this new genre, sometimes referred to as ambient house, ambient techno, ambient dub or simply ambient, saw the birth of a new wave of artists like the Orb and Aphex Twin.