The Collaborative International Dictionary of English v.0.48:

Psyche \Psy"che\, n. [L., fr. Gr. PSychh` Psyche, fr. psychh`
   the soul.]
   1. (Class Myth.) A lovely maiden, daughter of a king and
      mistress of Eros, or Cupid. She is regarded as the
      personification of the soul.
      [1913 Webster]

   2. The soul; the vital principle; the mind.
      [1913 Webster]

   3. [F. psych['e].] A cheval glass.
      [1913 Webster]

WordNet (r) 3.0 (2006):

psyche
    n 1: that which is responsible for one's thoughts and feelings;
         the seat of the faculty of reason; "his mind wandered"; "I
         couldn't get his words out of my head" [syn: mind,
         head, brain, psyche, nous]
    2: the immaterial part of a person; the actuating cause of an
       individual life [syn: soul, psyche]
    3: (Greek mythology) a beautiful princess loved by Cupid who
       visited her at night and told her she must not try to see
       him; became the personification of the soul