Crossing and transept

The crossing is the point in a large church at which the transept intersects the nave. This point is often marked externally by a tower or dome and internally by the piers and arches that are required to bear the weight of such a structure. The interior of the dome or tower may be one of the major architectural features of the interior of the church. In a centrally planned church such as Hagia Sophia, and typical of many Orthodox churches, the major interior space of the building is roofed by the dome.

The transept is symbolic of the arms of the Cross, but also provide space for congregation and for additional chapels. Transept chapels are often dedicated to a particular saint, or to a particular aspect in the life and ministry of Christ, such as the Nativity or the Resurrection. In some English cathedrals there is often a second transept containing chapels, to facilitate the saying of the Holy Office by clergy each day.

Choir and presbytery

In a church in which part of the body of the church extends beyond the transept, then this extension is architecturally termed the "choir". This architectural form is common in Norman and Gothic architecture. The choir, where it exists, normally contains the choir stalls, and the "sanctuary" and the "cathedra" (bishop's throne). The architectural "choir" is sometimes termed the "quire" to differentiate.

In those English cathedrals with two transepts, there is a further area beyond the choir which is called the Presbytery. This is where the priests or monks could make their private devotions. Often there are many additional chapels located towards the eastern end of a cathedral or abbey church.

Altar

The altar in a church is a table on which is laid the Blessed Sacrament of bread and wine for consecration by a priest prior to use in the rite of Communion. The main altar in a church is located in a designated space called the "sanctuary" ("holy place"). The word has passed into modern English with an altered meaning because a criminal who could gain access to this area without capture was thereby given the sanctuary of the church. Many churches have an additional altar placed further forward in the church, as well as altars in chapels. The altar of a Catholic church may be made of marble. In most Protestant and Anglican churches altars are of wood, symbolic of the table of the Last Supper rather than of a sacrificial altar.

The sanctuary is often separated from the body of the church by railings and screens, and, in the case of Orthodox churches, by an iconostasis which forms a complete visual as well as physical barrier. The sanctuary is usually the most ornately decorated part of a church, creating a visual focus towards the altar. This might be done in several ways. There might be a carved or painted altarpiece, a large carved screen, or a structure called a ciborium which form a canopy over the altar. In English churches that have a square eastern end, a very large stained glass window often fills the wall behind the altar.