ˌRussian ˌOrthodox ˈChurch, the BrE AmE
the main religion in Russia, which is a Christian church that formed in the 11th century by separating from the Catholic Church. The Orthodox Church is known for its very complicated religious ceremonies in which the words are mostly sung rather than spoken, and the Russian Orthodox Church is closely related to the ↑ Greek Orthodox Church .
—Russian Orthodox adjective