An Episcopal Dictionary of the Church

Episcopate, Episcopacy, Episcopos

Church governance under the leadership of bishops. The term is from the Greek for "overseer." The Prayer Book service for the ordination of a bishop states that a bishop "is called to be one with the apostles in proclaiming Christ's resurrection and interpreting the Gospel, and to testify to Christ's sovereignty as Lord of lords and King of kings." A bishop is called to guard the faith, unity, and discipline of the church, to celebrate and provide for the administration of the sacraments, to ordain priests and deacons and join in ordaining bishops, and to be a faithful pastor and wholesome example for the whole church. Bishops share in the leadership of the church throughout the world (BCP, p. 517). 

The terms may refer to the collective role of the order or office of bishops in the church. The "Historic Episcopate, locally adapted in the methods of its administration to the varying needs of the nations and peoples called of God into the unity of His Church" is one of the four points of the Chicago-Lambeth Quadrilateral. The 1886 General Convention of the Episcopal Church in Chicago identified the historic episcopate as an inherent part of the sacred deposit of Christian faith and order committed by Christ and his apostles to the church until the end of the world. The Convention accounted the historic episcopate to be one of four essentials for the restoration of unity among the divided branches of Christendom (BCP, p. 877). The Lambeth Conference of 1888 included the historic episcopate as one of the four points that supply a basis on which approach may be made towards Home Reunion (BCP, pp. 877-878). 
Episcopate or episcopacy may also indicate the body or college of bishops in a church or region, or the tenure or office of a bishop. See Chicago-Lambeth Quadrilateral; see Historic Episcopate.

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.