house wizard

( n.)

   [prob.: from ad-agency tradetalk, `house freak'] A hacker occupying a
   technical-specialist,  R&D, or systems position at a commercial shop.
   A  really  effective  house  wizard  can  have  influence  out of all
   proportion  to  his/her  ostensible rank and still not have to wear a
   suit. Used esp. of Unix wizards. The term house guru is equivalent.

[glossary]