WIZARD is a flag that affords an object control over nearly all other objects (the exception sometimes being that only God controls God). If a person is set WIZARD, they are a Wizard, unkillable, subject to fewer restrictions, and able to use wizard commands. In general, Wizards can do anything using #<number> or *<player>. Only player #1 can set and unset the WIZARD flag of other players. No Wizard can turn their own WIZARD flag off.
Under PennMUSH, Wizards can set the Wizard flag on an thing, room, or exit, and only God can set the Wizard flag on a player. For TinyMUX and TinyMUSH, only #1 (i.e., God) can set the Wizard flag on any object. Wizards cannot remove the flag from themselves.