sec ‧ tar ‧ i ‧ an /sekˈteəriən $ -ˈter-/ BrE AmE adjective
1 . sectarian violence/conflict/murder etc violence etc that is related to the strong feelings of people who belong to different religious groups:
people on both sides of the sectarian divide in Northern Ireland
2 . American English supporting a particular religious group and its beliefs:
a sectarian school
—sectarianism noun [uncountable]