In Orthodoxy, a useful distinction between vestments and clerical clothing is that if you have to bless it (or have it blessed) before you can wear it, it's a vestment. Otherwise, it's just clothes.
Inner Cassock: The inner cassock (simply called Cassock) is a floor length garment, usually black, worn by all clergy members, monastic's, and seminarians.
The Russian version, called a Podryasnik is double-breasted, closely fitted through the torso and flaring out to the skirt, and with a high collar buttoned off-center. The Greek version, called an Anteri or Rason, is somewhat fuller, gathered at the waist with a cord, and with a high collar buttoned in the front. The inner cassock is usually worn by all clergy members under their liturgical vestments.
Outer Cassock: Called a Ryasa or Exorason, the outer cassock is a large, flowing garment worn over the inner cassock by bishops, priests, deacons, and monastic's.
t is not worn by seminarians, readers or subdeacons. A Cassock Vest is sometimes worn over the Inner Cassock in cooler weather, especially in the Russian tradition. This is a closely fitted collarless vest with patch pockets, usually falling slightly below the waist.
Skufia: A soft-sided cap worn by monastic's or awarded to clergy as a mark of honor.
Kamilavka: A stiff hat worn by monastic's or awarded to clergy as a mark of honor. Kalimmavkhion or kalimafi is an item of clerical clothing worn by worn by Orthodox Christian monks (in which case it is black) or awarded to clergy as a mark of honor (in which case it is usually red or purple). It is a stiff hat that may be cylindrial with a flattened conical brim at the top (Greek style), flared and flat at the top (Russian style), or cylindrical and flat at the top (Serbian style).
Apostolnik: A veil worn either by nuns, either alone or with a skufia.
Epanokamelavkion: A veil extending over the back, worn with the kamilavka by all monastic's and bishops.
Klobuk: A kamilavka with an epanokamelavkion permanently attached; more common in the Russian tradition. It is an item of clerical clothing worn by Orthodox Christian rassophor monastic's, including bishops. It is a cloth veil, usually black, which is worn with a kamilavkion.
The epanokamelavkion is attached to the front of the kamilavkion and extends over the top to hang down the back. Monks leave the sides hanging, but nuns bring the sides together in front and fasten them under the chin, similar to an apostolnik.
A kamilavka with an epanokamelavkion permanently attached is called a klobuk; this is more common in the Russian tradition.
In the Orthodox Church, any member of the clergy, of whatever rank, will be vested when serving their particular function during the Divine Liturgy or other service. Usage is rooted in the early history of the church. The various vestments serve several different functions. The three forms of stole (Orarion, Epitrachelion, and Omophorion) are marks of rank. The three outer garments (Sticharion, Phelonion, and Sakkos) serve to distinguish the clergy from the laity. Some are practical (Zone and Epimanikia), holding the other vestments in place. Some (Nabedrennik and Epigonation) are awards of distinction.
In addition to these functions, most vestments carry a symbolic meaning as well. These symbolic meanings are often indicated by the prayer that the priest says as he puts each item on. These prayers are verses taken directly from the Old Testament, usually the Psalms. For example, the prayer for the Sticharion is from Isaiah 61:10: My soul will rejoice in the Lord, for he has clothed me with a garment of salvation and wrapped me in a robe of gladness; he has placed a crown on my head as on a bridegroom, and adorned me with beauty as a bride.
Liturgical colors are colors of vestments and church decorations within a Christian liturgy. The symbolism of purple, white, green, red, gold, black, and rose may serve to underline moods appropriate to a season of the liturgical year or may highlight a special occasion.
The Eastern Orthodox church does not have a universal system of colors, but only specifies "light" or "dark" vestments in the service books. However, Slavic-use churches and others influenced by Latin Catholicism have adopted a cycle of liturgical colors: white is used for Pascha, Christmas, and Theophany (in some areas bright red is used for Pascha); purple for weekends and black for weekdays in Lent; green for Pentecost and feasts of the Holy Cross (as well as, in parishes with a sense of humor, for St. Patrick's Day) ; blue for feasts of the Theotokos; red for feasts of martyrs and for the Nativity fast; and gold as the default