noun
state religion; established religion
Refers to a religion officially endorsed or adopted by a state. Often used in political, historical, or legal discussions.
その国ではキリスト教が国教とされている。
Christianity is the state religion in that country.
国教の制度は政教分離の原則と衝突することがある。
The system of an established religion can conflict with the principle of separation of church and state.