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).
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.
The English language word "church" is from the Old English word cirice, derived from West Germanic*kirika, which in turn comes from the Greek κυριακήkuriakē, meaning "of the Lord" (possessive form of κύριοςkurios "ruler" or "lord"). Kuriakē in the sense of "church" is most likely a shortening of κυριακὴ οἰκίαkuriakē oikia ("house of the Lord") or ἐκκλησία κυριακήekklēsia kuriakē ("congregation of the Lord"). Christian churches were sometimes called κυριακόνkuriakon (adjective meaning "of the Lord") in Greek starting in the 4th century, but ekklēsia and βασιλικήbasilikē were more common.