Sound in opinion or doctrine, especially in religious doctrine; hence, holding the Christian faith; believing the doctrines taught in the Scriptures; -- opposed to heretical and heterodox; as, an orthodox Christian.
According or congruous with the doctrines of Scripture, the creed of a church, the decree of a council, or the like; as, an orthodox opinion, book, etc.
The orthodox believers in God are divided into two camps, one of which maintains that the existence of God is as demonstrable as any mathematical proposition, while the other asserts that his existence is not demonstrable to the intellect. Annie Besant
One of the embarrassing problems for the early nineteenth-century champions of the Christian faith was that not one of the first six Presidents of the United States was an orthodox Christian. Mortimer Adler