To log on to a machine or connect to a network or BBS,

especially for purposes of entering a virtual reality

simulation such as a MUD or IRC (leaving is "jacking

out"). This term derives from cyberpunk SF, in which it was

used for the act of plugging an electrode set into neural

sockets in order to interface the brain directly to a virtual

reality. It is primarily used by MUD and IRC fans and younger

hackers on BBS systems.