Source : Webster's Revised Unabridged Dictionary (1913)

Architectural \Ar`chi*tec"tur*al\, a.
   Of or pertaining to the art of building; conformed to the
   rules of architecture. -- {Ar`chi*tec"tur*al*ly}, adv.

Source : WordNet®

architectural
     adj : of or pertaining to the art and science of architecture;
           "architectural history"; "architectural design"