An episcopal polity is a hierarchical form of church governance ("ecclesiastical polity") in which the chief local authorities are called bishops. (The word "bishop" derives, via the British Latin and Vulgar Latin term *ebiscopus/*biscopus, from the Ancient Greek επίσκοπος epískopos meaning "overseer".) It is the structure used by many of the major Christian Churches and denominations, such as the Roman Catholic, Eastern Orthodox, Oriental Orthodox, Church of the East, Anglican and Lutheran churches or denominations, and other churches founded independently from these lineages.
Churches with an episcopal polity are governed by bishops, practicing their authorities in the dioceses and conferences or synods. Their leadership is both sacramental and constitutional; as well as performing ordinations, confirmations, and consecrations, the bishop supervises the clergy within a local jurisdiction and is the representative both to secular structures and within the hierarchy of the church. Bishops are considered to derive their authority from an unbroken, personal apostolic succession from the Twelve Apostles of Jesus. Bishops with such authority are said to represent the historical episcopate or historic episcopate. Churches with this type of government usually believe that the Church requires episcopal government as described in the New Testament (see 1 Timothy 3 and 2 Timothy 1). In some systems, bishops may be subject to higher-ranking bishops (variously called archbishops, metropolitans, and/or patriarchs, depending upon the tradition). They also meet in councils or synods. These gatherings, subject to presidency by higher ranking bishops, usually make important decisions, though the synod or council may also be purely advisory.