The Collaborative International Dictionary of English v.0.48:

fundamentalism \fundamentalism\ n.
   1. A system of beliefs based on the interpretation of every
      word in the Bible, both old and new testaments, as literal
      truth. It is primarily held by a branch of American
      Protestants.
      [WordNet 1.5]

   2. The beliefs or practises based on a rigid adherence to
      some traditional doctrine; extreme conservatism; as,
      Moslem fundamentalism; the political fundamentalism of the
      Christian right.
      [PJC] fundamentalist

WordNet (r) 3.0 (2006):

fundamentalism
    n 1: the interpretation of every word in the sacred texts as
         literal truth