The Collaborative International Dictionary of English v.0.48:

Dissension \Dis*sen"sion\, n. [L. dissensio: cf. F. dissension.
   See Dissent.]
   Disagreement in opinion, usually of a violent character,
   producing warm debates or angry words; contention in words;
   partisan and contentious divisions; breach of friendship and
   union; strife; discord; quarrel.
   [1913 Webster]

         Paul and Barnabas had no small dissension and
         disputation with them.                   --Acts xv. 2.
   [1913 Webster]

         Debates, dissension, uproars are thy joy. --Dryden.
   [1913 Webster]

         A seditious person and raiser-up of dissension among
         the people.                              --Robynson
                                                  (More's
                                                  Utopia).
   [1913 Webster]

WordNet (r) 3.0 (2006):

dissension
    n 1: disagreement among those expected to cooperate [syn:
         discord, dissension]
    2: a conflict of people's opinions or actions or characters
       [syn: disagreement, dissension, dissonance] [ant:
       accord, agreement]