The Collaborative International Dictionary of English v.0.48:

Psychiatria \Psy*chi`a*tri"a\, Psychiatry \Psy*chi"a*try\, n.
   [NL. psychiatria, fr. Gr. ? the mind + ? healing.] (Med.)
   The application of the healing art to mental diseases.
   --Dunglison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

psychiatry
    n 1: the branch of medicine dealing with the diagnosis and
         treatment of mental disorders [syn: psychiatry,
         psychopathology, psychological medicine]