Minimalist Music

A style of music associated with the work of American composers La Monte Young, Terry Riley, Steve Reich, and Philip Glass. It was initially viewed as a form of experimental music called the New York Hypnotic School. Prominent features of the style include consonant harmony, steady pulse (if not immobile drones), stasis or gradual transformation, and often reiteration of musical phrases or smaller units such as figures, motifs, and cells. It may include features such as additive process and phase shifting which leads to what has been termed phase music. Minimal compositions that rely heavily on process techniques that follow strict rules are usually described using the term process music.
Leonard Meyer described minimal music in 1994: Because there is little sense of goal-directed motion, [minimal] music does not seem to move from one place to another. Within any musical segment there may be some sense of direction, but frequently the segments fail to lead to or imply one another. They simply follow one another.

Other Terms & Sub-Genres: Post-Minimalism, Process Music, Repetitive Music, Drone Music

Source: http://en.wikipedia.org/wiki/Minimalist_music