Bema is the Byzantine architectural name for the main sanctuary area behind the iconostasis.
In an Eastern Christian church, the bema is the elevated or sanctuary zone at the eastern end of the building. It commonly contains the altar and is associated with the clergy during the Divine Liturgy. In many churches, it is separated from the nave by an iconostasis.
The word comes from Greek and originally referred to a platform or raised step. Byzantine church architecture used the term for the sacred area that includes the altar space and, depending on the building, the apse and adjoining sanctuary compartments.
The bema is often confused with the naos, which is the main body of the church used by the congregation. The narthex is the entrance hall, while the atrium is an outer court found especially in earlier basilicas.