Is it ensure, insure, or assure?
late 14c., scisme, "dissention within the church," from Old French scisme, cisme "a cleft, split" (12c.), from Church Latin schisma, from Greek skhisma (genitive skhismatos) "division, cleft," in New Testament applied metaphorically to divisions in the Church (e.g. I Cor. xii.25), from stem of skhizein "to split" (see shed (v.)). Spelling restored 16c., but pronunciation unchanged. Often in reference to the Great Schism (1378-1417) in the Western Church.
a separation, an alienation causing divisions among Christians, who ought to be united (1 Cor. 12:25).
in Christianity, a break in the unity of the church