The Collaborative International Dictionary of English v.0.48:

Schism \Schism\, n. [OE. scisme, OF. cisme, scisme, F. schisme,
   L. schisma, Gr. schi`sma, fr. schi`zein to split; akin to L.
   scindere, Skr. chid, and prob. to E. shed, v.t. (which see);
   cf. Rescind, Schedule, Zest.]
   Division or separation; specifically (Eccl.), permanent
   division or separation in the Christian church; breach of
   unity among people of the same religious faith; the offense
   of seeking to produce division in a church without
   justifiable cause.
   [1913 Webster]

         Set bounds to our passions by reason, to our errors by
         truth, and to our schisms by charity.    --Eikon
                                                  Basilike.
   [1913 Webster]

   Greek schism (Eccl.), the separation of the Greek and Roman
      churches.

   Great schism, or Western schism (Eccl.) a schism in the
      Roman church in the latter part of the 14th century, on
      account of rival claimants to the papal throne.

   Schism act (Law), an act of the English Parliament
      requiring all teachers to conform to the Established
      Church, -- passed in 1714, repealed in 1719.
      [1913 Webster]

WordNet (r) 3.0 (2006):

schism
    n 1: division of a group into opposing factions; "another schism
         like that and they will wind up in bankruptcy" [syn:
         schism, split]
    2: the formal separation of a church into two churches or the
       withdrawal of one group over doctrinal differences

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "schism":
   affiliation, alienation, apostasy, betrayal, body, bolt, branch,
   breach, breach of friendship, break, breakaway, chasm, church,
   cleavage, cleft, communion, community, defection, denomination,
   dereliction, deserter, desertion, disaffection, disfavor,
   disruption, dissent, dissidence, disunion, disunity, divergence,
   dividedness, division, estrangement, faction, falling-out,
   fellowship, fissure, fracture, group, heterodoxy, misbelief,
   nonconformism, nonconformity, offshoot, open rupture, order,
   organization, party, persuasion, ratting, recall of ambassadors,
   religious order, rent, rift, rupture, school, secession, sect,
   sectarism, segment, separation, society, split, unorthodoxy,
   variety, version, walkout



Easton's 1897 Bible Dictionary:

Schism
   a separation, an alienation causing divisions among Christians,
   who ought to be united (1 Cor. 12:25).