The Collaborative International Dictionary of English v.0.48:

Talisman \Tal"is*man\, n.; pl. Talismans. [Sp., from Ar.
   tilism, tilsam, a magical image, pl. tilsam[=a]n, fr. Gr. ?
   tribute, tax, LGr., an initiation, incantation, from ? to
   complete, perform, to play taxes, to make perfect, to
   initiate, especially in the mysteries, fr. ? completion,
   end.]
   1. A magical figure cut or engraved under certain
      superstitious observances of the configuration of the
      heavens, to which wonderful effects are ascribed; the
      seal, figure, character, or image, of a heavenly sign,
      constellation, or planet, engraved on a sympathetic stone,
      or on a metal corresponding to the star, in order to
      receive its influence.
      [1913 Webster]

   2. Hence, something that produces extraordinary effects, esp.
      in averting or repelling evil; an amulet; a charm; as, a
      talisman to avert diseases. --Swift.
      [1913 Webster] Talismanic

WordNet (r) 3.0 (2006):

talisman
    n 1: a trinket or piece of jewelry usually hung about the neck
         and thought to be a magical protection against evil or
         disease [syn: amulet, talisman]