"Chancel

In church architecture, the chancel is the space around the altar in the sanctuary at the liturgical east end of a traditional Christian church building. It may terminate in an apse.

Following the exposition of the doctrine of transubstantiation at the fourth Lateran Council of 1215, clergy were required to ensure that the blessed sacrament was to be kept protected from irreverent access or abuse; and accordingly the area of the church used by the lay congregation was to be screened off from that used by the clergy. This distinction was enforced by the development of canon law, by which the construction and upkeep of the chancel was the responsibility of the rector, whereas the construction and upkeep of the nave was the responsibility of the parish.

As well as the altar, the chancel usually houses the credence table and seats for officiating and assisting ministers. In Anglican and Methodist churches it will usually include the choir. In some traditions, the pulpit and lectern may be in the chancel, but in others these functions are considered proper to the nave. .... "
[http://en.wikipedia.org/wiki/Chancel]

see drawing: [Распоред простора у православној цркви]
[http://sr.wikipedia.org/wiki/Датотека:Svetinja.svg]; [http://sr.wikipedia.org/sr/Наос]