A bishop (English derivation[a] from the New Testament of the Christian Bible Greek επίσκοπος, epískopos, "overseer", "guardian") is an ordained, consecrated, or appointed member of the Christian clergy who is generally entrusted with a position of authority and oversight.
Within the Catholic Church, Eastern Orthodox, Oriental Orthodox, Anglican, Old Catholic and Independent Catholic churches and in the Assyrian Church of the East, bishops claim apostolic succession, a direct historical lineage dating back to the original Twelve Apostles. Within these churches, bishops are seen as those who possess the full priesthood and can ordain clergy – including another bishop. Some Protestant churches including the Lutheran and Methodist churches have bishops serving similar functions as well, though not always understood to be within apostolic succession in the same way. One who has been ordained deacon, priest, and then bishop is understood to hold the fullness of the (ministerial) priesthood, given responsibility by Christ to govern, teach and sanctify the Body of Christ, members of the Faithful. Priests, deacons and lay ministers cooperate and assist their bishops in shepherding a flock.
The term epískopos (Ancient Greek: ἐπίσκοπος), meaning "overseer" in Greek, the early language of the Christian Church, was not from the earliest times clearly distinguished from the term presbýteros (literally: "elder" or "senior", origin of the modern English word priest), but the term was already clearly used in the sense of the order or office of bishop, distinct from that of presbyter in the writings attributed to Ignatius of Antioch  (died c. 110).