SIG
/sig/ n. (also common as a prefix in combining forms) A Special
Interest Group, in one of several technical areas, sponsored by the
Association for Computing Machinery; well-known ones include
SIGPLAN (the Special Interest Group on Programming Languages),
SIGARCH (the Special Interest Group for Computer Architecture) and
SIGGRAPH (the Special Interest Group for Computer Graphics).
Hackers, not surprisingly, like to overextend this naming
convention to less formal associations like SIGBEER (at ACM
conferences) and SIGFOOD (at University of Illinois).