Cathedra
Official seat or throne of the bishop in the cathedral of the diocese. The cathedra is considered to be the oldest insignia of the bishop's authority to preside over the church in the diocese. Historically, the bishop preached the sermon and presided at the eucharist from the cathedra, which was located in the center of the apse behind the altar. See Cathedral.
Glossary definitions provided courtesy of Church Publishing Incorporated, New York, NY,(All Rights reserved) from “An Episcopal Dictionary of the Church, A User Friendly Reference for Episcopalians,” Don S. Armentrout and Robert Boak Slocum, editors.