Where the meat lives.
Hackers are actually more willing to use this term than `cyberspace', because it's not speculative - we already have a running meatspace implementation (the universe).
Compare with CyberSpace.
CraigBox wanted this name for the WaikatoUniversity ACM chapter; however some people thought it had SexualConnotations or that no-one would get the joke.
6 pages link to MeatSpace: