The Collaborative International Dictionary of English v.0.48:

Internationalism \In`ter*na"tion*al*ism\, n.
   1. The state or principles of international interests and
      intercourse.
      [1913 Webster]

   2. The doctrines or organization of the International.
      [1913 Webster]

WordNet (r) 3.0 (2006):

internationalism
    n 1: the doctrine that nations should cooperate because their
         common interests are more important than their differences
         [ant: nationalism]
    2: quality of being international in scope; "he applauded the
       internationality of scientific terminology" [syn:
       internationality, internationalism]