The altar is the area at the east end of a church, usually behind an iconostasis (altar screen). The altar often is also referred to as the sanctuary. An Altar Table is located in the center of the altar as one enters through the Royal Doors in the iconostasis. This table is often referred to as the Holy Table. The word altar means "a place of sacrifice" in Hebrew (Gr. hieron; Sl. prestol).
Entry to the altar through the iconostasis from the nave is through the centrally placed royal doors or through the deacon's doors to the left and right of the royal doors. Only ordained men can pass through the royal doors. The altar may have other entries behind the iconostasis, but these are not used liturgically.
The altar table is usually a cube with each dimension of about one meter or cubit. The table may be made of wood or stone. The table is usually covered with a brocade covering, the color of which changes with the liturgical season. Atop the altar table is the tabernacle, a miniature shrine sometimes built in the form of a church, inside of which is a small ark containing the reserved Sacrament for use in communing the sick. Also, a multi-branch candle stand, usually with seven candles, is placed near the back of the table as one looks from the nave. Also kept on the altar is the book of the Gospels and the antimension, a silken cloth imprinted with an icon of Christ being prepared for burial, which has a relic sewn into it and bears the signature of the bishop. The Divine Liturgy must be served on an antimension even if the altar has been consecrated and contains relics. When not in use, the antimension is left in place wrapped in the eiliton, a cloth of plain silk, linen, or cotton.
The altar table may only be touched by subdeacons, deacons, priests or bishops, and nothing which is not itself consecrated or an object of veneration ought to be placed on it. Objects may also be placed on the altar table as part of the process for setting them aside for sacred use. For example, icons are usually blessed by laying them on the altar table for a period of time or for a certain number of Divine Liturgies before blessing them with holy water.
On left side of the altar is placed the table of preparation or prothesis upon which the sacramental offering of the Body and Blood of Christ is prepared in a service called the proskomedia before each liturgy.