Question:

In your answer to the meaning of "orthodox" in the OPC's name (see Meaning of Orthodox), you rightly say that it (generally) means "correct doctrine". However, your etymology of the word is not quite correct. The Greek word "doxa" means "worship" as in "correct worship." Clearly there's a relation between the two (the "regulative principle" applies to doctrine as well as worship) but there's a difference also.

Answer:

There are two questions involved here: First, does "Orthodox" mean (or primarily mean) "correct doctrine" or "correct worship"? Second, what does "Orthodox" mean in the name "Orthodox Presbyterian Church"?

In response to the first question there are two points that can be made:

(1) The standard dictionaries (including The New Oxford American Dictionary, the Random House Unabridged Dictionary, the Merriam-Webster Third New International Dictionary, and the Oxford Dictionary of English Etymology) when tracing the etymology of "orthodox" (from "ortho" + "doxa") give the original meaning (and current meaning) as "correct doctrine" or "straight opinion" or "right belief" rather than as "correct worship." (For further discussion of this point, see "Orthodox" Revisited - Part 1 and Part 3.)

(2) Outside such reference works, there are some who deal with the meaning of "orthodox" who do mention "correct worship" as a possible meaning. Of these, however, it may be observed that most (a) also mention "correct doctrine" as correct and also acceptable and (b) are almost always written from the standpoint of the Eastern Orthodox Church, which many would argue has a tradition of giving more attention to worship than to doctrine. (That is the point that will be developed here.)

Here I'll use some random examples from the World Wide Web, written from the perspective of the Eastern Orthodox Church:

The word Orthodox literally means right teaching or right worship, being derived from two Greek words: orthos (right) and doxa (teaching or worship).
  --The Orthodox Church.

The word Orthodox literally means "right teaching" or "right worship", being derived from two Greek words: orthos, "right," and doxa, "teaching" or "worship."
  --What Is the Orthodox Church?

The word Orthodox literally means "straight teaching" or "straight worship," being derived from two Greek words: orthos, "straight," and doxa, "teaching" or "worship."
  --What Is The Orthodox Church?

"Orthodox" is a combination of two Greek words—"orthos" and "doxa." "Orthos" means "correct;" "doxa" means "worship" or "doctrine." So the word "orthodox" signifies both "proper worship" and "correct doctrine.".
  --Introduction to The Orthodox Church.

The word Orthodox means the correct belief or right thinking. It takes the meaning from the Greek vocabulary. Orthos meaning "right" and the word doxa meaning "belief"."
  --The Orthodox Church.

The term Orthodox combines the adjective orthos, which means right, correct or true, and the noun doxa, which comes from the verb doxazo, "I hold an opinion," or "I believe." Hence "right belief," or "true doctrine." But in a deeper sense it also means "right worship," since doxazo can also mean "I glorify."
  --Introduction to the Orthodox Church.

Earlier I observed that outside the Eastern Orthodox Church there seems to be a consensus that "orthodox" refers to "correct doctrine" or "right opinion" or "right belief." To that, however, many in the Orthodox Church add (and often emphasize) the meaning of "correct worship," as I've just shown. Why is that?

One possible explanation is that the Orthodox Church is in reality not noted for an emphasis upon correct doctrine (some have observed that there is an amazing lack of Biblical literacy in the Church), but it is noted for its emphasis upon worship. Thus this particular interpretation of those within the Eastern Orthodox Church does serve the purpose of making the name "Orthodox" fit in better with their emphasis upon worship.

Does the Eastern Orthodox Church give primacy to worship over doctrine, as their own definition of "orthodox" may suggest?

Some who have studied Eastern Orthodoxy have noted significant doctrinal inadequacies. For example, Dr. Robert Letham, senior minister of Emmanuel Orthodox Presbyterian Church in Wilmington, Delaware, while he sees certain things to commend in the Eastern Orthodox tradition, also has this to say about the Eastern Church in his recent book on The Holy Trinity in Scripure, History, Theology and Worship:

...its doctrine of salvation, centered on incarnation, resurrection, and deification, leaves little room for the Atonement and justification.
  --The Holy Trinity in Scripure, History, Theology and Worship (P & R Publishing, 2004), p. 354.

But to those who have been brought up in the tradition of the Protestant Reformers, the Atonement and justification would certainly be regarded as essential doctrines of the Christian faith, and a church without a proper understanding of these doctrines would not be considered "orthodox"!

Dr. Letham (who is currently writing a book on Eastern Orthodoxy) is not alone in his conviction concerning the weakness of the Eastern Orthodox Church in the area of the Atonement and the area of justification. For instance, Lawrence W. Carrino, an Evangelical Free pastor, speaks of the same deficiency, in even stronger language:

What is truly concerning (particularly for Protestant converts to Orthodoxy) is that despite the wealth of Biblical evidence for man's salvation set primarily in terms of substitution and satisfaction; hence the imputed righteousness of Christ being the basis for man's approach to God in relationship or worship, the foundation [in Eastern Orthodoxy] moves to a process which is set in more neo-Platonic categories than Hebraic, and is built on scanty textual support...

I hold to the Reformed view of salvation because it is Biblical. It permeates every page of Scripture, and beautifully ties the covenants together in a tapestry of fulfillment which Jesus claimed He would accomplish through His substitutionary death on the cross (Matthew 5:17), which Paul reminds us, the gospel is the message of (1 Corinthians 1:18). Consider well the words of the Apostle Paul: 'More than that, I count all things to be loss in view of the surpassing value of knowing Christ Jesus my Lord, for whom I have suffered the loss of all things, and count them but rubbish in order that I may gain Christ, and may be found in Him, not having a righteousness of my own derived from the Law, but that which comes through faith in Christ, the righteousness which comes from God on the basis of faith/ (Philippians 3:8,9.)

This issue is not an academic discussion, but a matter of eternal life or death. The Scripture is clear on that matter upon which all other points are meaningful. If we do not know how to come into a relationship with God, all other considerations are terribly moot. I write this because I love and care for my Orthodox friends. This is not motivated by hatred or a desire to engage in needless disputations. There is much to appreciate and admire about Eastern Orthodoxy. However, on this essential point, the official teaching of the church is about as unorthodox as it gets, when measured by the standard of the Word of God, and not the varied opinions of men, whether they be Greek or Latin, ancient or contemporary."

  --http://www.christiantruth.com/orthodoxycominghome.html.

Carrino is not an Orthodox Presbyterian, but I think he is correct when he as a Protestant pastor argues that the doctrine of the Atonement and the doctrine of justification are "the basis for man's approach to God in relationship or worship." Correct worship is founded upon correct doctrine. You cannot properly worship God without being brought into a saving relationship with Him through the substitutionary Atonement of Christ or without being justified by faith (See Ephesians 2:8-9, "For it is by grace you have been saved, through faith--and this not from yourselves, it is the gift of God--not by works, so that no one can boast," NIV.)

Similarly, Rick Ware of Probe Ministries—also not an Orthodox Presbyterian—seems to be on target when he makes this criticism:

The worship service has supreme importance in Orthodoxy; it is more important than doctrine and the disciplines of the Christian life.
  --http://www.probe.org/docs/east-orth.html.

In his book on The Holy Trinity, Dr. Letham argues that "The Eastern doctrine of the Trinity ... undermines our knowledge of God, and, in so doing, implicitly quetions the faithfulness and reliability of God" (p. 354). Correct doctrine is again at issue within the Eastern Orthodox Church, which may or may not relate to their preferring to define "orthodox" as "correct worship" rather than "correct doctrinie."

We've considered at length the question, "Does 'Orthodox' mean (or primarily mean) 'correct doctrine' or 'correct worship'?" We have seen that both by etymology and by usage, "orthodox" means "correct doctrine" rather than "correct worship" (although correct worship is based on correct doctrine). Most who seek to define "orthodox" as "correct worship" speak as members of the Eastern Orthodox Church (with its emphasis upon worship over doctrine) and almost always admit that "correct doctrine" is an acceptable alternative rendering, so there is no need to surrender "correct doctrine" as the preferred meaning. But that leaves us with an important question that we will consider next: "What does 'Orthodox' mean in the name 'Orthodox Presbyterian Church'?"

(Coming up: more on "correct doctrine" and "correct worship" and the early history of the OPC.)