Interior of a Church Building
       Historic Floor Plan

1. Communion table, most often called the altar.
2. Communion railing, also called the chancel railing, with provisions for kneeling.
3. Pulpit, used by clergy for gospel readings and sermons.
4. Lectern with Bible, used by lay readers for scripture readings.
5. Boundary between nave and sanctuary; usually three steps up. In Orthodox churches, the boundary may be in a slightly different location and may consist of a screen covered with icons.
6. Congregation. Western churches have pews, but in most Orthodox churches the congregation still stands.
7. The sanctuary or chancel.
8. The nave, where the congregation sits

The choir may be located behind the chancel, to one or both sides of the chancel, behind the congregation, or on a balcony behind the congregation. Sometimes the choir is often located on both sides of the chancel so that the building can be shaped like a cross. The choir is positioned so that it can be heard, without consideration for its visibility.

After the congregation is seated, the choir, lay leaders, and clergy (in that order) enter in a procession up the aisle. The minister who delivers the sermon sits near the pulpit. There may two seats within the chancel railing, one for the minister who conducts the communion and one for a lay helper. Leaders face the communion table when addressing God, whether in prayer or song, because they are acting as part of the congregation. Leaders face the congregation only during announcements, scripture readings, and the sermon.

This floor plan goes back to the first public buildings that were erected for Christian worship. With local variations, it is used by Orthodox, Roman Catholic, Anglican, Lutheran, and Methodist churches, among others. In a large number of recently constructed Roman Catholic churches it is now common for the nave to be a semicircle that surrounds the chancel, for a theater-in-the-round effect.

In western churches, the congregation has a speaking role in the service; that is, the clergy lead the congregation, who actually perform the bulk of the service. This makes the service seem complex to the visitor. The first part of the service emphasizes Bible readings and the sermon, and it follows the general plan of a synagogue service. The second half of the service, if present, consists of communion. Any part of the service, except communion, may be led by a lay person. Most Bible readings and prayers are offered by lay leaders. The gospel reading and the sermon are generally done by clergy. The congregation generally stands to sing or respond, sits to listen, and kneels to pray.

Orthodox churches follow the same plan, except that there are generally no pews and often the entire service is sung responsively by the clergy and the choir. The role of the congregation is simply to stand in awe and prayer. Seats are provided for the disabled. Individuals in the congregation are allowed to kneel or lie prostrate on the floor only when they are offering penitential prayer and only if penitential prayer is appropriate. (For example, penitential prayer is not considered appropriate during the Easter service.) Orthodox worship has not changed at all for over 1,000 years.