2.
a. A formal breach of union within a Christian church.
b. The offense of attempting to produce such a breach.

3. Disunion; discord.

[Middle English scisme, from Old French, from Latin schisma, schismat-, from Greek skhisma, from skhizein, to split; see skei- in Indo-European roots.]

Usage Note: The word schism, which was originally spelled scisme in English, is traditionally pronounced (szm). However, in the 16th century the word was respelled with an initial sch in order to conform to its Latin and Greek forms. From this spelling arose the pronunciation (skzm). Long regarded as incorrect, it became so common in both British and American English that it gained acceptability as a standard variant. Evidence indicates, however, that it is now the preferred pronunciation, at least in American English. In a recent survey 61 percent of the Usage Panel indicated that they use (skzm), while 31 percent said they use (szm). A smaller number, 8 percent, preferred a third pronunciation, (shzm).

schism [skizz-um]
Noun :  the division of a group, esp. a religious group, into opposing factions, due to differences in doctrine [Greek skhizein to split]

schismatic adj

schism
a division especially peculiar to a Christian church or a religious body. — schismatic, n. — schismatical, adj.

Noun

1. schism – division of a group into opposing factions; “another schism like that and they will wind up in bankruptcy”
split
division – the act or process of dividing
2. schism – the formal separation of a church into two churches or the withdrawal of one group over doctrinal differences
falling out, severance, rupture, rift, breach, break – a personal or social separation (as between opposing factions); “they hoped to avoid a break in relations”

source: thefreedictionary.com

.