An offshoot of free jazz
incorporating musicians from different disciplines. Spin a CD by Peter Brötzmann
, Joëlle Léandre
, Derek Bailey
, Evan Parker
, or one of dozens of other fine musicians.
A further abstraction of jazz, in that it isn't just about improvising notes and chord voicings, but about sounds, structures, and textures as well - anything (Swiss folk tunes, Japanese gagaku, turntablism, bird calls...) can go into the blender, as long as the player or group makes it work. Ultimately, it's all just music. My writeup is less relevant than your participating ears.