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]

Moby Thesaurus II by Grady Ward, 1.0:

100 Moby Thesaurus words for "dissension":
   aggressiveness, agreement to disagree, alienation, altercation,
   antagonism, antipathy, apostasy, argument, argumentation,
   bad blood, bellicosity, belligerence, bickering, clashing,
   collision, combativeness, competition, conflict, contention,
   contentiousness, contradiction, contrariety, contrariness,
   controversy, counter-culture, cross-purposes, difference,
   disaccord, disaccordance, disagreement, disapprobation,
   disapproval, discord, discordance, discordancy, discrepancy,
   disharmony, disparity, dispute, dissatisfaction, dissent,
   dissentience, dissidence, dissonance, disunion, disunity,
   divergence, diversity, dropping out, enmity, faction, factiousness,
   flak, fractiousness, friction, hostility, inaccordance, inequality,
   infighting, inimicalness, irascibility, irritability, jarring,
   litigiousness, minority opinion, negation, negativeness,
   nonagreement, nonassent, nonconcurrence, nonconformity, nonconsent,
   noncooperation, obstinacy, opposition, oppugnancy, partisan spirit,
   partisanship, perverseness, pugnacity, quarrel, quarrelsomeness,
   recalcitrance, recusance, recusancy, refractoriness, rejection,
   repudiation, repugnance, rivalry, secession, shrewishness, strife,
   uncooperativeness, underground, unharmoniousness, variance, vying,
   withdrawal, wrangle