Orthodox \Or"tho*dox\, a. [L. orthodoxus, Gr. 'orqo`doxos; 'orqo`s right, true + do`xa opinion, dokei^n to think, seem; cf. F. orthodoxe. See Ortho-, Dogma.]

1. 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.

2. 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.

3. Approved; conventional.

He saluted me on both cheeks in the orthodox manner. --H. R. Haweis.

Note: The term orthodox differs in its use among the various Christian communions. The Greek Church styles itself the ``Holy Orthodox Apostolic Church,'' regarding all other bodies of Christians as more or less heterodox. The Roman Catholic Church regards the Protestant churches as heterodox in many points. In the United States the term orthodox is frequently used with reference to divergent views on the doctrine of the Trinity. Thus it has been common to speak of the Trinitarian Congregational churches in distinction from the Unitarian, as Orthodox. The name is also applied to the conservative, in distinction from the ``liberal'', or Hicksite, body in the Society of Friends. --Schaff-Herzog Encyc.

Source: Webster's Revised Unabridged Dictionary (1913)