Answer:

Greetings in the Lord Jesus Christ. You asked about the origin of "orthodox" in the name of the Orthodox Presbyterian Church and if we have any connection with the Eastern Orthodox Church.

1. The short answer is "No," for our origins are in the Reformation, which took place in the Western (Latin) Church, not in the Eastern (Orthodox) Church.

2. A slightly longer answer is that "orthodox" (meaning "correct doctrine") was chosen for its contrast to "liberal Protestant" unbelief and not for any contrast to the historic Christianity of the Western Church or for any reference to the Greek Orthodox Church's criticisms of the Roman Catholic Church (although the OPC, of course, would be in agreement with historic Protestantism's criticisms of the Roman Catholic Church).

When the liberals of the large Presbyterian Church, USA (PCUSA) defrocked Professor J. G. Machen of Princeton Seminary (and six other ministers in other presbyteries) in an administrative move and denied him liberty of conscience to serve Christ in the work at hand that the Lord had given him, a sizable segment of the PCUSA followed the forced exodus of Machen and called themselves the "Presbyterian Church of America." The use of this name was challenged and court action was threatened if the despised "splinter" group did not drop a name that, the PCUSA charged, would be confusing to a large segment of the American public.

A young former student of Machen's at Westminster Theological Seminary, Rev. Everett DeVelde of Baltimore, suggested that the use of the anglicized form of the two Greek words of the New Testament for "correct, straight" ("ortho") and for "doctrine" ("dox") would neatly solve the problem of distinguishing the new group from the old group.

The liberal group, the PCUSA, despised enforcing orthodoxy in its midst. Many of its ministers boasted of their rejection of much of the Westminster Confession of Faith, a historic doctrinal standard of traditional Presbyterianism. More than that, 1500 signed the "Auburn Affirmation," which denied the Bible's teaching on five fundamentals of the historic Christian faith. Many boasted that their heterodoxy enabled them to keep their respectability in society because their new views fit in with modern science and critical Bible scholarship.

DeVelde's suggestion of joining "orthodox" and "Presbyterian" caught on, in spite of some pastors' noting the possibly confusing connection you have suggested. The PC, USA had no objections to the new name. (For further information on the change of name from the Presbyterian Church of America to the Orthodox Presbyterian Church, see This Week in Church History.)

I hope that the preceding explanation has been helpful to you.