Ambient
Ambient music can exist pleasantly in the background or powerfully in the foreground. Brian Eno coined the term "ambient music" in the 1970s when he released a series of wildly experimental, seminal albums that included Discrete Music and Music for Airports. These albums contained music meant to exist in the background -- music that could be forgotten about but was nonetheless present, continuing to impact on the listener.
Years later, when electronic music dance music began to spread across the globe, ambient music flourished as a soothing counterpart to the hyperactivity of the dance floor. Ambient music became popularly known as a form of electronic music that had been stripped of most (if not all) of its beats and vocals, leaving only the soothing electronic sounds and melodies.
But ambient music has always been about much more than the chill-out room at the party or dance club. It is music that opens us to the sounds of the world around us. Ambient music might be a field recording from Indonesia, a quiet improvised guitar piece, or warm electronic sounds that slowly ebb and flow. As always, the best way to understand is simply to listen. 
