As you are probably aware, there is not a high degree of unity in Eastern Orthodoxy in English-speaking nations, especially in North America (cf. Phyletism, autocephaly, controversy concerning autocephaly and the OCA, controversy over the broad appointment of metropolitans). However, there is somewhat general consensus on on the orders. But it should be noted that not all Orthodox Christians will recognize all of the titles within the orders, and some consider them to be in a slightly different order. Also, many of the English titles borrow heavily from the Greek conventions, so some of those will be noted. With that said, there are three major orders in Orthodoxy:
- Bishops (episkopos, ἐπίσκοπος)
- Presbyters (πρεσβύτερος, more commonly called priests, hiereus, ἱερεύς)
- Deacons (diakonos, διάκονος)
There are also two minor orders:
There were formerly other minor orders but most have fallen into disuse (such as doorkeepers, exorcists, and acolytes). The major orders can be further subdivided.
- Ecumenical Patriarch of Constantinople. The first in honor among all Orthodox bishops (first among equals, as the Pope of Rome once was prior to schisming). He is a special patriarch (which is often considered equal to an archbishop in various traditions, different only in honor).
- Patriarch. A bishop who is the head of an ancient or ethnic Church (originally there were only five in the early Church, comprising the Pentarchy).
- Archbishop. The head of an Orthodox country or capital city (depending on the tradition, these may be above, below, or equal to metropolitans. This is an area of disagreement and difference of practice).
- Metropolitan. A bishop who is the head of a large city or a diocese (see note on archbishop).
- Bishop. Oversees a diocese or special community of Orthodox Christians. Possesses the full priesthood and may ordain clergy. Chosen only from monastic priests (archimandrites).
- Titular / Auxiliary Bishop. A bishop who is not in charge of a diocese. Assistant to a diocesan bishop. Sometimes also granted as a role of honor to those whose dioceses no longer exist.
Presbyter / Priest
- Archimandrite. A title of honor given only to monastic priests. This originally referred to a supervisory abbot appointed over other abbots and/or monasteries, or to the abbot of a prominent monastery. It has come to more or less be an honorary title for hieromonks. Only archimandrites are eligible to be appointed as Bishops (which is why I've listed it first, although in many ways they are equal to or below protopresbyters and/or archpriests).
- Protopresbyter / Protopriest. A title of honor given only to non-monastic priests. It literally means "first elder" (some traditions do not distinguish between a protopresbyter and an archpriest).
- Archpriest. A title of honor given only to non-monastic priests. A priest placed over several parishes may sometimes be appointed to this role (see note for protopresbyter).
- Hieromonk. Literally, a "priest-monk." A monk who is also an ordained priest.
- Presbyter / Priest. An ordained elder who may administer the sacraments.
- Protodeacon. A title of honor given only to non-monastic deacons. It literally means "first servant/server" (some traditions consider archdeacons above protodeacons).
- Archdeacon. The senior deacon in a diocese, responsible for serving at hierarchical services (services with the bishop). Usually he travels with the bishop. Some traditions only give this title to monastic deacons (see note for protodeacon).
- Hierodeacon. A deacon-monk. A monk who has been ordained as a deacon.
- Deacon. An ordained servant who may assist the priest in the administration of the sacraments (as well as a variety of other duties).
Concerning the minor orders, a subdeacon (also called a hypodeacon) may assist the bishop and/or priest in various ways (but not with the administration of the sacraments). The ordination to subdeacon is not performed during Divine Liturgy nor at the altar as it is a minor order. He may be assigned any of the other roles of the minor orders such as Reader (but also former minor orders that have fallen into disuse such as Cantor, Catechist, or other leadership roles in the community). While canon law does consider the ordination of subdeacons to be binding on their marital status, many do not enforce this or consider the ordination to be of a different sort. Thus the canon laws concerning the marriage or celibacy of candidates is generally only enforced for the major orders.
A reader (or lector) is ordained by the bishop to read during services and in the Divine Liturgy. This role developed due to low literacy rates in past history, so being able to read was a special gift. The only way scripture was normally heard by early Christians was when it was publicly read in the church. He may also be assigned any of the other roles of the minor orders other than subdeacon (such as Cantor, Catechist, or other leadership roles in the community).