op

op /op/ n.  1. In England and Ireland, common verbal
   abbreviation for `operator', as in system operator.  Less common in
   the U.S., where {sysop} seems to be preferred.  2. [IRC] Someone
   who is endowed with privileges on {IRC}, not limited to a
   particular channel.  These are generally people who are in charge
   of the IRC server at their particular site.  Sometimes used
   interchangeably with {CHOP}.  Compare {sysop}.