This is a definition which has always puzzled me. Gilles Peterson (the DJ) is credited with coining the term as an alternative or extension of the Acid House craze that was sweeping the dance floors of the UK in the late 80s. But even as I sit here listening to a very funky George Benson version of Miles Davis's So What it is still not (to my mind) a well defined genre. Some would have you believe that the defining characteristic of Acid Jazz is that it is a fusion of various elements such as funk, soul and bossa nova alongside the more traditional jazz. Others would assert that it is the mixing of jazz with more modern progressive ideas such as hip hop, drum'n'bass or jungle and none of these retro ideas. Anyone care to help me out here?