Ambient Music
From http://www.intuitivemusic.com

The modern term of ambient music was first coined by Brian Eno in 1974 when the artist was convalescent in a London hospital after having being run over a taxi. While Eno was listening a classic harp record with difficulties the sound got mixed with the ambience sounds of the city and the rain. This inspired him to create a kind of music that could provide to the listener with similar ambience sensations using abstract musical structures and ambient sounds. A year before this event, Brian Eno had already recorded the first of a series of ambient oriented works along with King Crimson’s guitarist Robert Fripp. Fripp and Eno’s work was based upon the use of electronic loop and it represented a new style in music closer to avant-gard music than rock. In 1978 Brian Eno released the first album of the series Ambient, “Music for Airports”, which was the first formal ambient work by the artist.

Ambient music is characterized by the use of relaxed and environmental sound atmospheres and abstract patterns, very often related with sound experimentalism and most of the time instrumental.

Erik Satie was one of the first 20th Century composers to become a pioneer in ambient oriented compositions with the “Trois Gymnopédies” suite. Other ambient pioneering composers were Debussy, Edgar Varesse, Karlheinz Stockhausen and John Cage. Pierre Schaeffer’s musique concrete music was also an influential element in the manipulation of recorded ambient sounds.

One of the most important pioneers of the genre was Raymond Scott, who in 1963 released a series of albums called “Soothing Sounds for Baby” intended to be an “aural toy” for babies, which turned out to be the first ambient electronic work ever released.

Other artists who contributed to the ambient music in the early 70’s were Pink Floyd, Tangerine Dream and Ashra.

During the late 80’s a new music style called new age, often used with therapeutic intentions, appeared in the U.S. new age music is apparently similar to the most relaxing works of ambient music, but completely different in the musical attitude and structure language. During these years an array of solo artists who were producing quiet and relaxing music, both electronic and acoustic, were put in the big sack of new age and ambient music. Some of the most important artists are Suzanne Ciani, Kitaro, Harold Budd, Roger Eno, and John Hassell.

In the 90’s electronic musicians like Aphex Twin, influenced by vintage ambient, developed the style by combining with dance and electronica. Other relevant ambient electronica artists are Future Sound of London, Banco de Gaia, Biosphere, The Orb, and Pete Namlook.

Meditation Music
For medition music there has been no good definition from the Internet so I will try to explain it, to what I think is correct. Correct me, if I am wrong.

Meditation music is similar to ambient music, that is really slow for drifting, sleeping or for meditation. However there are a few big differences bewteen the 2 styles. First meditation music has more of a nature feel to it... To be continued....

Very good description.

Useful link here: http://fusionanomaly.net/ambient.html