Sh is a metaprogramming language for programmable GPUs. Programmable GPUs are graphics processing units that execute some operations with higher efficiency than CPUs. In practice, this offloads a lot of graphical processing to specialized hardware rather than software and allows the video card to be treated as a general-purpose secondary processor.
As of August 2006, it is no longer maintained. RapidMind Inc. was formed to commercialize the research behind Sh.