schism

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A separation or division into factions.
2. n. A formal breach of union within a Christian church.
3. n. The offense of attempting to produce such a breach.
4. n. Disunion; discord.

Century Dictionary and Cyclopedia

1. n. Division or separation; specifically, in ecclesiastical usage, a formal separation within or from an existing church or religious body, on account of some difference of opinion with regard to matters of faith or discipline.
2. n. The offense of seeking to produce a division in a church. In the authorized version of the New Testament the word schism occurs but once (1 Cor. xii. 25); but in the Greek Testament the Greek word σχίσ, σ1μα occurs eight times, being rendered in the English version ‘rent’ (Mat. ix. 16) and ‘division’ (John vii. 43; 1 Cor. xi. 18). From the simple meaning of division in the church the word has come to indicate a separation from the church, and now in ecclesiastical usage is employed solely to indicate a formal withdrawal from the church and the formation of or the uniting with a new organization. See def. 1.
3. n. A schismatic body.

Wiktionary

1. n. A split or separation within a group or organization, typically caused by discord.
2. n. A formal division or split within a religious body.
3. n. a split within Christianity whereby a group no longer recognizes the Bishop of Rome as the head of the Church, but shares essentially the same beliefs with the Church of Rome. In other words, a political split without the introduction of heresy.

GNU Webster's 1913

1. n. Division or separation 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.

WordNet 3.0

1. n. the formal separation of a church into two churches or the withdrawal of one group over doctrinal differences
2. n. division of a group into opposing factions