There is a point that has been made a couple times that I don't think has been stressed enough (as indicated by the fact the the OP has asked the question after those points were made):
(Also, forgive me if I do not transliterate these Greek words into English as properly as some would like)
There are two concepts in both the Hebrew and the Greek (I will only deal with the Greek) that each have their own respective word in those languages. One is the concept of an "elder", and that is the word "presvyteros" (i.e., "presbyter"). The word "presvyteros" is used throughout the Old Testament (by that I mean the Greek translation of the Old Testament, the Septuagint, or LXX) in cases such as the "elders" that Moses appointed to assist him in administering the affairs of Israel. It is also used in the New Testament when Christ deals with the "elders" and other leaders of Judea, in addition to the church office of elder/presbyter.
The other concept is that of someone who approaches God on behalf of the people". The Greek word used in both the Old Testament and the New Testament is the word "hiereus". The word "heireus" is used throughout the Old Testament to refer to the Levites and the sons of Aaron, as well as to those from the surrounding pagan religions who were in charge of invoking those gods.
Unfortunately, for us English speakers, we do not have two separate words to convey those two separate concepts. However, one of those words has made its way into the English language, and that is the word "presvyteros", which is the same as the christian office of "elder". That word was shortened a little bit in Latin to the form "prestus", from which we get the word "priest". But there is not a distinct word for the Greek word "hiereus", and the word "priest" is used in the English language to denote both of the concepts.
So it is important that when we use the word "priest" we understand the context, and if we are referring to a "presvyteros" or to a "hiereus". An Orthodox priest is an Orthodox "presvyteros". Christ is our high "hiereus", while all of us (i.e., the baptized) are all a "hiereus".
Does that make sense, Walter?