Orthodox churches generally take one of several shapes that have a particular mystical significance. The most common shape is an oblong or rectangular shape, imitating the form of a ship. As a ship, under the guidance of a master helmsman conveys men through the stormy seas to a calm harbor, so the Church, guided by Christ, carries men unharmed across the stormy seas of sin and strife to the peaceful haven of the Kingdom of Heaven. Churches are also frequently built in the form of a Cross to proclaim that we are saved through faith in the Crucified Christ, for Whom Christians are prepared to suffer all things. Less frequently churches are built in the shape of a circle, signifying that the Church of Christ shall exist for all eternity (the circle being one of the symbols of eternity) or in the shape of an octagon, signifying a star, for the Church, like a star, guides a man through the darkness of sin which encompasses him. Because of the difficulties of internal arrangement, however, the latter two shapes are not often used.
Almost always Orthodox churches are oriented East West, with the main entrance of the building at the West end. This symbolizes the entrance of the worshipper from the darkness of sin (the West) into the light of Truth (the East). This rule is violated only if the building had been previously constructed for another purpose, or if services are conducted in a private home, for example, when the entrance and main portion have been arranged according to convenience.
On the roof of Orthodox churches are usually found one or more cupolas (towers with rounded or pointed roofs), called crests or summits. One cupola signifies Christ, the sole head of the Christian community; three cupolas symbolize the Most-Holy Trinity; five cupolas represent Christ and the four Evangelists; seven cupolas symbolize the Seven Ecumenical Councils which formulated the basic dogmas of the Orthodox Church, as well as the general use in the Church of the sacred number seven; nine cupolas represent the traditional nine ranks of Angels; and thirteen cupolas signify Christ and the Twelve Apostles.
A peculiar feature of Russian Orthodox churches is the presence of onion-shaped domes on top of the cupolas. In the early history of the Russian Church, especially in Kiev, the first capital, the domes of the churches followed the typical Byzantine rounded style, but later, especially after the Mongol Period, Russian churches tended toward the onion domes, which, in many places, became quite stylized. Historians are not in agreement as to the origin of this particular style, but some point to the possible influence of Persia on this peculiar feature of Russian church architecture, while others argue that since this style was more popular in the far North of Russia, it had a practical application, in that the shape was particularly suited to shed the large amounts of snow common in the region.
Every cupola, or where there is none, the roof, is crowned by a Cross, the instrument of our salvation. The Cross may take one of many different shapes, generally according to the national tradition of a particular local Church. In the Russian Church, the most common form is the so-called three-bar Cross, consisting of the usual crossbeam, a shorter crossbeam above that and another, slanted, crossbeam below. Symbolically, the three bars represent, from the top, the signboard on which was written, in Hebrew, Latin and Greek, Jesus of Nazareth, the King of the Jews (John 19:19); the main crossbeam, to which the hands of Jesus were nailed; the lower portion, to which His precious feet were nailed.
The three-bar representation existed in Christian art from very early times in Byzantium, although usually without the bottom bar slanted, which is particularly Russian. The origin of this slanted footboard is not known, but in the symbolism of the Russian Church, the most common explanation is that it is the pointing upward to Paradise for the Good Thief on Jesus' right and downward to Hell for the Thief on His left (Luke 23). Sometimes the bottoms of the Crosses found on Russian churches will be adorned with a crescent. In 1486, Tsar Ivan IV (the Terrible) conquered the city of Kazan which had been under the rule of Moslem Tatars, and in remembrance of this, he decreed that from henceforth the Islamic crescent be placed at the bottom of the Crosses to signify the victory of the Cross (Christianity) over the Crescent (Islam).
The interior of an Orthodox church is divided into several parts. One enters the church through the Porch where, in ancient times, the Weepers (Penitents forbidden to enter the church proper) stood. From the Porch one entered the Vestibule (Narthex; Lity Greek; Pritvor Russian), in ancient times a large, spacious place, wherein the Catechumens received instruction while preparing for Baptism, and also where Penitents excluded from Holy Communion stood. Here was found the Baptismal Font and it is here that the Church Typikon specifies that penitential services (such as Compline, Nocturns and the Hours) be served. In modern times, except for certain monasteries, the Vestibule has fallen into disuse with the decline of the Catechumenate, and has virtually disappeared in church architecture.
The main body of the church is the Nave, separated from the Sanctuary (Altar) by an Icon screen with doors, called the Iconostasis (Icon stand). The walls of the Nave are usually decorated with Icons and frescoes or paintings, before many of which are hanging lit lamps (lampadas). On each side, near the front, are usually found portable Icons called Banners which are fastened to staffs. These are carried in triumphant processions in like manner to the ancient military banners of victory, which they imitate. Especially noticeable in traditional Orthodox churches is the absence of any seating (except perhaps for benches placed along the walls and at the rear). The Holy Fathers deemed it disrespectful for anyone to sit during the Divine services (except at certain explicit moments of instruction or Psalm reading) and the open spaces were seen to be especially conducive to the many bows and prostrations typical of Orthodox worship.
At the extreme Eastern end of the church is found the Altar (or Sanctuary), with two small rooms the Sacristy and the Vestry at either side, separated from the Nave by the Iconostasis. The Iconostasis is placed near the edge of the platform upon which stands the Altar and the part of the platform which projects out into the Nave is called the Soleas (an elevated place) where the Communicants stand to receive Holy Communion and where the Celebrants come out for public prayers, sermons, etc. At either side of the Soleas are places for two Choirs, called the Kleros (meaning lots, since in ancient times Readers and Singers were chosen by lots). At the front of the Soleas, before the Holy Doors, is an extension of the Soleas, called the Ambo (ascent) which is the specific spot where the faithful receive Communion and where sermons are given. In many Greek churches, there is a separate place to the side of the Soleas for the delivery of sermons the Pulpit.
Sometimes placed in the center of the Nave is a raised platform called the Cathedra. Here the Bishop stands when he is vested and it is from here that parts of the services are performed by him. In some churches a special throne is set at the side of the Nave for the Bishop's use.
Excerpt taken from "These Truths We Hold - The Holy Orthodox Church: Her Life and Teachings". Compiled and Edited by A Monk of St. Tikhon's Monastery. Copyright 1986 by the St. Tikhon's Seminary Press, South Canaan, Pennsylvania 18459.