The Collaborative International Dictionary of English v.0.48:

Modernism \Mod"ern*ism\, n.
   1. Modern practice; a thing of recent date; esp., a modern
      usage or mode of expression.
      [1913 Webster]

   2. Certain methods and tendencies which, in Biblical
      questions, apologetics, and the theory of dogma, in the
      endeavor to reconcile the doctrines of the Roman Catholic
      Church with the conclusions of modern science, replace the
      authority of the church by purely subjective criteria; --
      so called officially by Pope Pius X.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

modernism
    n 1: genre of art and literature that makes a self-conscious
         break with previous genres
    2: the quality of being current or of the present; "a shopping
       mall would instill a spirit of modernity into this village"
       [syn: modernity, modernness, modernism,
       contemporaneity, contemporaneousness]
    3: practices typical of contemporary life or thought