"Christian Church" is an ecclesiological term generally used by Protestants to refer to the whole group of people belonging to Christianity throughout the history of Christianity. In this understanding, "Christian Church" does not refer to a particular Christian denomination but to the body of all believers. Some Christian traditions, however, believe that the term "Christian Church" or "Church" applies only to a specific historic Christian body or institution (e.g., the Catholic Church, the Eastern Orthodox Church, the Oriental Orthodox Churches, or the Assyrian Church of the East). The Four Marks of the Church first expressed in the Nicene Creed are that the Church is One (a unified Body of Particular Churches in full communion of doctrines and faith with each other), Holy (a sanctified and deified Body), Catholic (Universal and containing the fullness of Truth in itself), and Apostolic (its hierarchy, doctrines, and faith can be traced back to the Apostles).Thus, the majority of Christians globally (particularly of the apostolic churches listed above, as well as some Anglo-Catholics) consider the Christian Church as a visible and institutional "societas perfecta" enlivened with supernatural grace, while Protestants generally understand the Church to be an invisible reality not identifiable with any specific earthly institution, denomination, or network of affiliated churches. Others equate the Church with particular groups that share certain essential elements of doctrine and practice, though divided on other points of doctrine and government (such as the branch theory as taught by some Anglicans).
Most English translations of the New Testament generally use the word "church" as a translation of the Ancient Greek: ἐκκλησία, translit. ecclesia, found in the original Greek texts, which generally meant an "assembly". This term appears in two verses of the Gospel of Matthew, 24 verses of the Acts of the Apostles, 58 verses of the Pauline epistles (including the earliest instances of its use in relation to a Christian body), two verses of the Letter to the Hebrews, one verse of the Epistle of James, three verses of the Third Epistle of John, and 19 verses of the Book of Revelation. In total, ἐκκλησία appears in the New Testament text 114 times, although not every instance is a technical reference to the church.In the New Testament, the term ἐκκλησία is used for local communities as well as in a universal sense to mean all believers. Traditionally, only orthodox believers are considered part of the true church, but convictions of what is orthodox have long varied, as many churches (not only the ones officially using the term "Orthodox" in their names) consider themselves to be orthodox and other Christians to be heterodox.