The Collaborative International Dictionary of English v.0.48:

thaumaturgy \thau"ma*tur`gy\ (th[add]`m[.a]*t[^u]r"j[y^]), n.
   [Gr. qaymatourgi`a.]
   The act or art of performing something wonderful; magic;
   legerdemain. --T. Warton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

thaumaturgy
    n 1: any art that invokes supernatural powers [syn: magic,
         thaumaturgy]
    2: an illusory feat; considered magical by naive observers [syn:
       magic trick, conjuring trick, trick, magic,
       legerdemain, conjuration, thaumaturgy, illusion,
       deception]